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1
Hu, Jinghua, Samuel G. Wittekind et Maureen M. Barr. « STAM and Hrs Down-Regulate Ciliary TRP Receptors ». Molecular Biology of the Cell 18, no 9 (septembre 2007) : 3277–89. http://dx.doi.org/10.1091/mbc.e07-03-0239.
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Cilia are endowed with membrane receptors, channels, and signaling components whose localization and function must be tightly controlled. In primary cilia of mammalian kidney epithelia and sensory cilia of Caenorhabditis elegans neurons, polycystin-1 (PC1) and transient receptor polycystin-2 channel (TRPP2 or PC2), function together as a mechanosensory receptor-channel complex. Despite the importance of the polycystins in sensory transduction, the mechanisms that regulate polycystin activity and localization, or ciliary membrane receptors in general, remain poorly understood. We demonstrate that signal transduction adaptor molecule STAM-1A interacts with C. elegans LOV-1 (PC1), and that STAM functions with hepatocyte growth factor–regulated tyrosine kinase substrate (Hrs) on early endosomes to direct the LOV-1-PKD-2 complex for lysosomal degradation. In a stam-1 mutant, both LOV-1 and PKD-2 improperly accumulate at the ciliary base. Conversely, overexpression of STAM or Hrs promotes the removal of PKD-2 from cilia, culminating in sensory behavioral defects. These data reveal that the STAM-Hrs complex, which down-regulates ligand-activated growth factor receptors from the cell surface of yeast and mammalian cells, also regulates the localization and signaling of a ciliary PC1 receptor-TRPP2 complex.
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Manolache, Alexandra, Teodora Stratulat et Alexandru Babeș. « Modulation of Transient Receptor Potential (TRP) channels by tyrosine phosphorylation ». Reviews in Biological and Biomedical Sciences 3, no 1 (4 juillet 2020) : 77–87. http://dx.doi.org/10.31178/rbbs.2020.3.1.5.
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Transient Receptor Potential (TRP) channels are a superfamily of polymodal, non-selective receptors, expressed in the nervous system and several other tissues, where they play many physiological or pathological roles. TRP channels are sensitive to a diverse range of stimuli, such as temperature, osmolarity, oxidative stress, external compounds and intracellular signaling molecules. The activity of TRP channels can be modulated by protein phosphorylation, including tyrosine phosphorylation. In this review, we present the studies carried out so far regarding the modulation of TRP channels by tyrosine phosphorylation.
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Lezama-García, Karina, Daniel Mota-Rojas, Alfredo M. F. Pereira, Julio Martínez-Burnes, Marcelo Ghezzi, Adriana Domínguez, Jocelyn Gómez et al. « Transient Receptor Potential (TRP) and Thermoregulation in Animals : Structural Biology and Neurophysiological Aspects ». Animals 12, no 1 (2 janvier 2022) : 106. http://dx.doi.org/10.3390/ani12010106.
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This review presents and analyzes recent scientific findings on the structure, physiology, and neurotransmission mechanisms of transient receptor potential (TRP) and their function in the thermoregulation of mammals. The aim is to better understand the functionality of these receptors and their role in maintaining the temperature of animals, or those susceptible to thermal stress. The majority of peripheral receptors are TRP cation channels formed from transmembrane proteins that function as transductors through changes in the membrane potential. TRP are classified into seven families and two groups. The data gathered for this review include controversial aspects because we do not fully know the mechanisms that operate the opening and closing of the TRP gates. Deductions, however, suggest the intervention of mechanisms related to G protein-coupled receptors, dephosphorylation, and ligands. Several questions emerge from the review as well. For example, the future uses of these data for controlling thermoregulatory disorders and the invitation to researchers to conduct more extensive studies to broaden our understanding of these mechanisms and achieve substantial advances in controlling fever, hyperthermia, and hypothermia.
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Zaccor, Nicholas W., Charlotte J. Sumner et Solomon H. Snyder. « The nonselective cation channel TRPV4 inhibits angiotensin II receptors ». Journal of Biological Chemistry 295, no 29 (3 juin 2020) : 9986–97. http://dx.doi.org/10.1074/jbc.ra120.014325.
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G-protein–coupled receptors (GPCRs) are a ubiquitously expressed family of receptor proteins that regulate many physiological functions and other proteins. They act through two dissociable signaling pathways: the exchange of GDP to GTP by linked G-proteins and the recruitment of β-arrestins. GPCRs modulate several members of the transient receptor potential (TRP) channel family of nonselective cation channels. How TRP channels reciprocally regulate GPCR signaling is less well-explored. Here, using an array of biochemical approaches, including immunoprecipitation and fluorescence, calcium imaging, phosphate radiolabeling, and a β-arrestin–dependent luciferase assay, we characterize a GPCR–TRP channel pair, angiotensin II receptor type 1 (AT1R), and transient receptor potential vanilloid 4 (TRPV4), in primary murine choroid plexus epithelial cells and immortalized cell lines. We found that AT1R and TRPV4 are binding partners and that activation of AT1R by angiotensin II (ANGII) elicits β-arrestin–dependent inhibition and internalization of TRPV4. Activating TRPV4 with endogenous and synthetic agonists inhibited angiotensin II–mediated G-protein–associated second messenger accumulation, AT1R receptor phosphorylation, and β-arrestin recruitment. We also noted that TRPV4 inhibits AT1R phosphorylation by activating the calcium-activated phosphatase calcineurin in a Ca2+/calmodulin–dependent manner, preventing β-arrestin recruitment and receptor internalization. These findings suggest that when TRP channels and GPCRs are co-expressed in the same tissues, many of these channels can inhibit GPCR desensitization.
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Rigano, Daniela, Carmen Formisano et Orazio Taglialatela-Scafati. « Marine Metabolites Modulating CB Receptors and TRP Channels ». Planta Medica 82, no 09/10 (22 mars 2016) : 761–66. http://dx.doi.org/10.1055/s-0042-101352.
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Maliszewska, Justyna, Milena Jankowska, Hanna Kletkiewicz, Maria Stankiewicz et Justyna Rogalska. « Effect of Capsaicin and Other Thermo-TRP Agonists on Thermoregulatory Processes in the American Cockroach ». Molecules 23, no 12 (18 décembre 2018) : 3360. http://dx.doi.org/10.3390/molecules23123360.
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Capsaicin is known to activate heat receptor TRPV1 and induce changes in thermoregulatory processes of mammals. However, the mechanism by which capsaicin induces thermoregulatory responses in invertebrates is unknown. Insect thermoreceptors belong to the TRP receptors family, and are known to be activated not only by temperature, but also by other stimuli. In the following study, we evaluated the effects of different ligands that have been shown to activate (allyl isothiocyanate) or inhibit (camphor) heat receptors, as well as, activate (camphor) or inhibit (menthol and thymol) cold receptors in insects. Moreover, we decided to determine the effect of agonist (capsaicin) and antagonist (capsazepine) of mammalian heat receptor on the American cockroach’s thermoregulatory processes. We observed that capsaicin induced the decrease of the head temperature of immobilized cockroaches. Moreover, the examined ligands induced preference for colder environments, when insects were allowed to choose the ambient temperature. Camphor exposure resulted in a preference for warm environments, but the changes in body temperature were not observed. The results suggest that capsaicin acts on the heat receptor in cockroaches and that TRP receptors are involved in cockroaches’ thermosensation.
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Ojiro, Ichie, Hiromi Nishio, Toyomi Yamazaki-Ito, Shogo Nakano, Sohei Ito, Yoshikazu Toyohara, Tadahiro Hiramoto, Yuko Terada et Keisuke Ito. « Trp-Trp acts as a multifunctional blocker for human bitter taste receptors, hTAS2R14, hTAS2R16, hTAS2R43, and hTAS2R46 ». Bioscience, Biotechnology, and Biochemistry 85, no 6 (12 avril 2021) : 1526–29. http://dx.doi.org/10.1093/bbb/zbab061.
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ABSTRACT Many functional food ingredients activate human bitter taste receptors (hTAS2Rs). In this study, A novel inhibitor, Trp-Trp, for hTAS2R14 was identified by searching for the agonist peptide's analogs. Trp-Trp also inhibited hTAS2R16, hTAS2R43, and hTAS2R46, which share the same agonists with hTAS2R14. The multifunctional characteristic of Trp-Trp is advantageous for use as bitterness-masking agents in functional foods.
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Thapa, Dibesh, Brentton Barrett, Fulye Argunhan et Susan D. Brain. « Influence of Cold-TRP Receptors on Cold-Influenced Behaviour ». Pharmaceuticals 15, no 1 (28 décembre 2021) : 42. http://dx.doi.org/10.3390/ph15010042.
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The transient receptor potential (TRP) channels, TRPA1 and TRPM8, are thermo-receptors that detect cold and cool temperatures and play pivotal roles in mediating the cold-induced vascular response. In this study, we investigated the role of TRPA1 and TRPM8 in the thermoregulatory behavioural responses to environmental cold exposure by measuring core body temperature and locomotor activity using a telemetry device that was surgically implanted in mice. The core body temperature of mice that were cooled at 4 °C over 3 h was increased and this was accompanied by an increase in UCP-1 and TRPM8 level as detected by Western blot. We then established an effective route, by which the TRP antagonists could be administered orally with palatable food. This avoids the physical restraint of mice, which is crucial as that could influence the behavioural results. Using selective pharmacological antagonists A967079 and AMTB for TRPA1 and TRPM8 receptors, respectively, we show that TRPM8, but not TRPA1, plays a direct role in thermoregulation response to whole body cold exposure in the mouse. Additionally, we provide evidence of increased TRPM8 levels after cold exposure which could be a protective response to increase core body temperature to counter cold.
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Fernandes, E. S., S. Awal, R. Karadaghi et S. D. Brain. « TRP Receptors in Arthritis, Gaining Knowledge for Translation from Experimental Models ». Open Pain Journal 6, no 1 (8 mars 2013) : 50–61. http://dx.doi.org/10.2174/1876386301306010050.
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Arthritis is a condition characterised by mainly pain, reduced joint movement and signs of inflammation, such as swelling. The disorder has many different types, of which osteoarthritis (a degenerative joint disease) and rheumatoid arthritis (a chronic autoimmune disease) are the two most common forms. There are >6 million sufferers in the UK and both conditions have a huge potential to impair capabilities and contribute to social and economic burdens. Whilst there are a wide range of arthritic therapies available, many patients under treatment complain of poor pain relief. Thus there is a need for novel therapeutic approaches, and the transient receptor potential (TRP) family of receptor channels has been investigated. One particular area of recent research has been the ligand-gated transient receptor potential vanilloid 1 (TRPV1) channel. Findings from numerous pre-clinical models and scientific studies have shown that TRPV1 desensitisation, or the use of TRPV1 antagonists alleviates pain and some inflammatory aspects. New findings have started to unveil the potential of other TRP channels in mediating arthritic pain and inflammation. With the understanding that the currently available treatments for arthritis are limited, researchers have looked into the exciting prospect that TRP receptor antagonists may be developed into effective, specific drugs, which would potentially protect against the complications of arthritis. These antagonists are still under development, although only data from studies from pre-clinical models are currently available. This review acts to summarize knowledge of the potential influence of TRP receptors in arthritis to date.
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Shabir, Saqib, William Cross, Lisa A. Kirkwood, Joanna F. Pearson, Peter A. Appleby, Dawn Walker, Ian Eardley et Jennifer Southgate. « Functional expression of purinergic P2 receptors and transient receptor potential channels by the human urothelium ». American Journal of Physiology-Renal Physiology 305, no 3 (1 août 2013) : F396—F406. http://dx.doi.org/10.1152/ajprenal.00127.2013.
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In addition to its role as a physical barrier, the urothelium is considered to play an active role in mechanosensation. A key mechanism is the release of transient mediators that activate purinergic P2 receptors and transient receptor potential (TRP) channels to effect changes in intracellular Ca2+. Despite the implied importance of these receptors and channels in urothelial tissue homeostasis and dysfunctional bladder disease, little is known about their functional expression by the human urothelium. To evaluate the expression and function of P2X and P2Y receptors and TRP channels, the human ureter and bladder were used to separate urothelial and stromal tissues for RNA isolation and cell culture. RT-PCR using stringently designed primer sets was used to establish which P2 and TRP species were expressed at the transcript level, and selective agonists/antagonists were used to confirm functional expression by monitoring changes in intracellular Ca2+ and in a scratch repair assay. The results confirmed the functional expression of P2Y4 receptors and excluded nonexpressed receptors/channels (P2X1, P2X3, P2X6, P2Y6, P2Y11, TRPV5, and TRPM8), while a dearth of specific agonists confounded the functional validation of expressed P2X2, P2X4, P2Y1, P2Y2, TRPV2, TRPV3, TRPV6 and TRPM7 receptors/channels. Although a conventional response was elicited in control stromal-derived cells, the urothelial cell response to well-characterized TRPV1 and TRPV4 agonists/antagonists revealed unexpected anomalies. In addition, agonists that invoked an increase in intracellular Ca2+ promoted urothelial scratch repair, presumably through the release of ATP. The study raises important questions about the ligand selectivity of receptor/channel targets expressed by the urothelium. These pathways are important in urothelial tissue homeostasis, and this opens the possibility of selective drug targeting.
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Nesterov, Alexandre, Christian Spalthoff, Ramani Kandasamy, Radoslav Katana, Nancy B. Rankl, Marta Andrés, Philipp Jähde et al. « TRP Channels in Insect Stretch Receptors as Insecticide Targets ». Neuron 86, no 3 (mai 2015) : 665–71. http://dx.doi.org/10.1016/j.neuron.2015.04.001.
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Caterina, Michael J. « Vanilloid receptors take a TRP beyond the sensory afferent☆ ». Pain 105, no 1 (septembre 2003) : 5–9. http://dx.doi.org/10.1016/s0304-3959(03)00259-8.
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Putney, J. W. « TRP, inositol 1,4,5-trisphosphate receptors, and capacitative calcium entry ». Proceedings of the National Academy of Sciences 96, no 26 (21 décembre 1999) : 14669–71. http://dx.doi.org/10.1073/pnas.96.26.14669.
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Méndez-Reséndiz, Karina Angélica, Óscar Enciso-Pablo, Ricardo González-Ramírez, Rebeca Juárez-Contreras, Tamara Rosenbaum et Sara Luz Morales-Lázaro. « Steroids and TRP Channels : A Close Relationship ». International Journal of Molecular Sciences 21, no 11 (27 mai 2020) : 3819. http://dx.doi.org/10.3390/ijms21113819.
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Transient receptor potential (TRP) channels are remarkable transmembrane protein complexes that are essential for the physiology of the tissues in which they are expressed. They function as non-selective cation channels allowing for the signal transduction of several chemical, physical and thermal stimuli and modifying cell function. These channels play pivotal roles in the nervous and reproductive systems, kidney, pancreas, lung, bone, intestine, among others. TRP channels are finely modulated by different mechanisms: regulation of their function and/or by control of their expression or cellular/subcellular localization. These mechanisms are subject to being affected by several endogenously-produced compounds, some of which are of a lipidic nature such as steroids. Fascinatingly, steroids and TRP channels closely interplay to modulate several physiological events. Certain TRP channels are affected by the typical genomic long-term effects of steroids but others are also targets for non-genomic actions of some steroids that act as direct ligands of these receptors, as will be reviewed here.
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Balemans, Dafne, Guy E. Boeckxstaens, Karel Talavera et Mira M. Wouters. « Transient receptor potential ion channel function in sensory transduction and cellular signaling cascades underlying visceral hypersensitivity ». American Journal of Physiology-Gastrointestinal and Liver Physiology 312, no 6 (1 juin 2017) : G635—G648. http://dx.doi.org/10.1152/ajpgi.00401.2016.
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Visceral hypersensitivity is an important mechanism underlying increased abdominal pain perception in functional gastrointestinal disorders including functional dyspepsia, irritable bowel syndrome, and inflammatory bowel disease in remission. Although the exact pathophysiological mechanisms are poorly understood, recent studies described upregulation and altered functions of nociceptors and their signaling pathways in aberrant visceral nociception, in particular the transient receptor potential (TRP) channel family. A variety of TRP channels are present in the gastrointestinal tract (TRPV1, TRPV3, TRPV4, TRPA1, TRPM2, TRPM5, and TRPM8), and modulation of their function by increased activation or sensitization (decreased activation threshold) or altered expression in visceral afferents have been reported in visceral hypersensitivity. TRP channels directly detect or transduce osmotic, mechanical, thermal, and chemosensory stimuli. In addition, pro-inflammatory mediators released in tissue damage or inflammation can activate receptors of the G protein-coupled receptor superfamily leading to TRP channel sensitization and activation, which amplify pain and neurogenic inflammation. In this review, we highlight the present knowledge on the functional roles of neuronal TRP channels in visceral hypersensitivity and discuss the signaling pathways that underlie TRP channel modulation. We propose that a better understanding of TRP channels and their modulators may facilitate the development of more selective and effective therapies to treat visceral hypersensitivity.
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Bradshaw, Heather B., Siham Raboune et Jennifer L. Hollis. « Opportunistic activation of TRP receptors by endogenous lipids : Exploiting lipidomics to understand TRP receptor cellular communication ». Life Sciences 92, no 8-9 (mars 2013) : 404–9. http://dx.doi.org/10.1016/j.lfs.2012.11.008.
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HAFDI, Zakia, Sylvianne COUETTE, Etienne COMOY, Dominique PRIE, Claude AMIEL et Gerard FRIEDLANDER. « Locally formed 5-hydroxytryptamine stimulates phosphate transport in cultured opossum kidney cells and in rat kidney ». Biochemical Journal 320, no 2 (1 décembre 1996) : 615–21. http://dx.doi.org/10.1042/bj3200615.
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Renal proximal tubular cells have been shown to express aromatic l-amino acid decarboxylase (l-AAAD), which converts l-dopa into dopamine and 5-hydroxytryptophan [(OH)Trp] into 5-hydroxytryptamine (5-HT; serotonin). Because 5-HT receptors have been demonstrated in proximal cells, we hypothesized that 5-HT may act as an autocrine/paracrine modulator of proximal transport. We evaluated this possibility in opossum kidney (OK) cells, a renal epithelial cell line with a proximal phenotype expressing 5-HT1B receptors, and in intact anaesthetized rats. 5-HT synthesis by OK cells increased with incubation time and (OH)Trp concentration, and was abolished by benserazide, an l-AAAD inhibitor. 5-HT reversed parathyroid hormone (PTH)-induced cAMP accumulation in a pertussis toxin-sensitive manner and reduced the PTH inhibition of Pi uptake without affecting the NaPi-4 mRNA level. The effects of 5-HT on cAMP generation and Na–Pi co-transport were reproduced by (OH)Trp, except in the presence of benserazide, and by l-propranolol and dihydroergotamine, two 5-HT1B receptor agonists. In rats, (OH)Trp and dihydroergotamine decreased fractional Pi excretion. Benserazide abolished the effect of (OH)Trp but not that of dihydroergotamine. In conclusion: (i) locally generated 5-HT blunts the inhibitory effect of PTH on Na–Pi co-transport in OK cells; (ii) endogenous 5-HT decreases Pi excretion in rats; and (iii) 5-HT is a paracrine modulator involved in the physiological regulation of renal Pi transport.
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Tiruppathi, C., H. Lum, T. T. Andersen, J. W. Fenton et A. B. Malik. « Thrombin receptor 14-amino acid peptide binds to endothelial cells and stimulates calcium transients ». American Journal of Physiology-Lung Cellular and Molecular Physiology 263, no 5 (1 novembre 1992) : L595—L601. http://dx.doi.org/10.1152/ajplung.1992.263.5.l595.
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We examined the binding characteristics of the recently described thrombin receptor amino-terminal peptide, SFLLRNPNDKYEPF (T. K. H. Vu, D. T. Hung, V. I. Wheaton, and S. R. Coughlin. Cell 64: 1057-1068, 1991), termed TRP-14, and its effect in activating intracellular calcium transients in pulmonary vascular endothelial cells. Binding of 125I-labeled TRP-14 was found to be saturable with a affinity constant of 2 microM and maximum binding of 41 pmol/mg of cell protein. The 125I-labeled TRP-14 also interacted with bovine pulmonary microvessel endothelial cells, human umbilical vein endothelial cells, and porcine pulmonary artery smooth muscle cells. Binding of 125I-labeled diisopropylphosphoryl (DIP)-alpha-thrombin, which is catalytically inactive but binds to thrombin receptors, was not inhibited by TRP-14 or vice versa, indicating that TRP-14 did not compete for the alpha-thrombin binding site(s) on the endothelial cell surface. TRP-14 (> 1 microM) increased the concentration of intracellular calcium ([Ca2+]i) in endothelial cells with kinetics similar to the increase in [Ca2+]i triggered by alpha-thrombin. In contrast, DIP-alpha-thrombin did not increase [Ca2+]i and also did not prevent the rise in [Ca2+]i induced by the subsequent challenge with either TRP-14 or alpha-thrombin. Because the generation of TRP-14 by the proteolytically active forms of thrombin stimulated a rise in endothelial [Ca2+]i, TRP-14 may be the agonist responsible for the activation of the alpha-thrombin receptor in pulmonary vascular endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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Farhan, Muhammad, Fatima Riaz, Sana Wali et Hamna Rafiq. « Desensitization of 5-HT-1A Somatodentritic Receptors in Tryptophan Treated and Co-treated Rats Induced by Methylphenidate ». Current Clinical Pharmacology 14, no 2 (25 octobre 2019) : 125–31. http://dx.doi.org/10.2174/1574884713666181112123309.
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Background:Psychostimulants can induce behavioral sensitization by their chronic use. The main target for the action of these drugs is dopamine, neither epinephrine nor serotonin transporters. Serotonin is synthesized by the precursor L-tryptophan. Tryptophan and methylphenidate being 5-HT agonists, both increase the level of serotonin thereby causing desensitization of 5-HT1a receptors. The present study investigated whether behavioral sensitization induced by Methylphenidate is decreased in tryptophan administrated animals.Methods:The Experiment was divided into 2 phases (1). Behavioral effects of repeated administration of TRP 100 mg/kg and MPD for 14 days in three groups; (i) water (ii) MPD 1.0 mg/kg (iii) TRP. To explore the locomotor effects of treatment, the activity was monitored in a familiar and novel environment. (2) Behavioral consequences of repeatedly administrated MPD (1.0 mg/kg) on pretreated TRP (100 mg/kg) and MPD (1.0 mg/kg) animals following Co-MPD and TRP for 14 days, rats were divided in three groups (i) water, (ii) MPD and (iii) TRP as mentioned in Experiment no 1. After two weeks six subgroups were assigned i.e. (i) water-saline, (ii) water- MPD, (iii) TRP-saline (iv) TRP-MPD (v) MPD-saline and (vi) MPD-MPD+TRP and treated for further 14 days. Locomotor behavior was monitored in familiar environment on the next day and in novel environment on alternate days of each administration.Results:The Results from phase 1 showed increased activity in both (TRP and MPD) treatments. However, the results of phase 2 showed significant decrease in methylphenidate-induced behavioral sensitization by both pretreatment and co-administration with TRP.Conclusion:The present study suggests the potential of tryptophan to decrease the risk of behavioral sensitization induced by methylphenidate.
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Keh, S. M., P. Facer, A. Yehia, G. Sandhu, H. A. Saleh et P. Anand. « The menthol and cold sensation receptor TRPM8 in normal human nasal mucosa and rhinitis ». Rhinology journal 49, no 4 (1 octobre 2011) : 453–57. http://dx.doi.org/10.4193/rhino11.089.
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Background: Menthol and cold sensation trigger symptoms and reflex responses in the upper airway, but the underlying molecular mechanisms are unknown. We have therefore studied nerve fibres expressing the menthol and cold receptor TRPM8 in normal human mucosa, and in rhinitis. TRPM8 nerve fibres were compared with those expressing other TRP receptors including TRPV1 (capsaicin and heat receptor), and TRPA1 (mechano-cold receptor). Methods: Immunohistology and image-analysis were used to study TRP receptors in biopsies of nasal turbinate from control subjects, patients with allergic rhinitis, and non-allergic rhinitis. Results: TRPM8-immunoreactive nerve fibres were observed in the sub-epithelium, and were profuse around blood vessels in deeper regions, where they were markedly greater in number than TRPV1+ fibers. Image analysis of TRPM8 in sub-epithelial and vascular regions showed no significant differences between control and the rhinitis patient groups. TRPA1-immunoreactivity was weak and seen rarely in nerve fibres. Conclusion: We show that TRPM8 nerve fibres are abundant in nasal mucosa particularly around blood vessels, and may mediate neurovascular reflexes. TRPM8 antagonists deserve consideration for therapeutic trial in rhinitis.
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Caterina, Michael J. « TRP Channel Cannabinoid Receptors in Skin Sensation, Homeostasis, and Inflammation ». ACS Chemical Neuroscience 5, no 11 (17 juin 2014) : 1107–16. http://dx.doi.org/10.1021/cn5000919.
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Colenso, Charlotte K., Deny Cabezas, Danielle Granata, Vincenzo Carnevale, Juan C. Opazo, Christopher A. Ahern et Sebastian E. Brauchi. « Intra-Molecular Connectivity in Sensory Receptors of the TRP Family ». Biophysical Journal 112, no 3 (février 2017) : 8a. http://dx.doi.org/10.1016/j.bpj.2016.11.071.
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Steinritz, Dirk, Bernhard Stenger, Alexander Dietrich, Thomas Gudermann et Tanja Popp. « TRPs in Tox : Involvement of Transient Receptor Potential-Channels in Chemical-Induced Organ Toxicity—A Structured Review ». Cells 7, no 8 (7 août 2018) : 98. http://dx.doi.org/10.3390/cells7080098.
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Chemicals can exhibit significant toxic properties. While for most compounds, unspecific cell damaging processes are assumed, a plethora of chemicals exhibit characteristic odors, suggesting a more specific interaction with the human body. During the last few years, G-protein-coupled receptors and especially chemosensory ion channels of the transient receptor potential family (TRP channels) were identified as defined targets for several chemicals. In some cases, TRP channels were suggested as being causal for toxicity. Therefore, these channels have moved into the spotlight of toxicological research. In this review, we screened available literature in PubMed that deals with the role of chemical-sensing TRP channels in specific organ systems. TRPA1, TRPM and TRPV channels were identified as essential chemosensors in the nervous system, the upper and lower airways, colon, pancreas, bladder, skin, the cardiovascular system, and the eyes. Regarding TRP channel subtypes, A1, M8, and V1 were found most frequently associated with toxicity. They are followed by V4, while other TRP channels (C1, C4, M5) are only less abundantly expressed in this context. Moreover, TRPA1, M8, V1 are co-expressed in most organs. This review summarizes organ-specific toxicological roles of TRP channels.
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Fliegert, R., A. Gasser et A. H. Guse. « Regulation of calcium signalling by adenine-based second messengers ». Biochemical Society Transactions 35, no 1 (22 janvier 2007) : 109–14. http://dx.doi.org/10.1042/bst0350109.
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cADPR [cyclic ADPR (ADP-ribose)], NAADP (nicotinic acid–adenine dinucleotide phosphate) and ADPR belong to the family of adenine-containing second messengers. They are metabolically related and are all involved in the regulation of cellular Ca2+ homoeostasis. Activation of specific plasma membrane receptors is connected to cADPR formation in many cell types and tissues. In contrast receptor-mediated formation of NAADP and ADPR has been shown only in a few selected cellular systems. The intracellular Ca2+ channel triggered by cADPR is the RyR (ryanodine receptor); in the case of NAADP, both activation of RyR and a novel Ca2+ channel have been proposed. In contrast, ADPR opens the non-specific cation channel TRPM2 [TRP (transient receptor potential) melastatin 2] that belongs to the TRP family of ion channels.
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Aroke, Edwin, Keesha Powell-Roach, Rosario Jaime-Lara, Markos Tesfaye, Abhrarup Roy, Pamela Jackson et Paule Joseph. « Taste the Pain : The Role of TRP Channels in Pain and Taste Perception ». International Journal of Molecular Sciences 21, no 16 (18 août 2020) : 5929. http://dx.doi.org/10.3390/ijms21165929.
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Transient receptor potential (TRP) channels are a superfamily of cation transmembrane proteins that are expressed in many tissues and respond to many sensory stimuli. TRP channels play a role in sensory signaling for taste, thermosensation, mechanosensation, and nociception. Activation of TRP channels (e.g., TRPM5) in taste receptors by food/chemicals (e.g., capsaicin) is essential in the acquisition of nutrients, which fuel metabolism, growth, and development. Pain signals from these nociceptors are essential for harm avoidance. Dysfunctional TRP channels have been associated with neuropathic pain, inflammation, and reduced ability to detect taste stimuli. Humans have long recognized the relationship between taste and pain. However, the mechanisms and relationship among these taste–pain sensorial experiences are not fully understood. This article provides a narrative review of literature examining the role of TRP channels on taste and pain perception. Genomic variability in the TRPV1 gene has been associated with alterations in various pain conditions. Moreover, polymorphisms of the TRPV1 gene have been associated with alterations in salty taste sensitivity and salt preference. Studies of genetic variations in TRP genes or modulation of TRP pathways may increase our understanding of the shared biological mediators of pain and taste, leading to therapeutic interventions to treat many diseases.
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Wolfgang, Werner, Alekos Simoni, Carla Gentile et Ralf Stanewsky. « The Pyrexia transient receptor potential channel mediates circadian clock synchronization to low temperature cycles in Drosophila melanogaster ». Proceedings of the Royal Society B : Biological Sciences 280, no 1768 (7 octobre 2013) : 20130959. http://dx.doi.org/10.1098/rspb.2013.0959.
Texte intégralRésumé :
Circadian clocks are endogenous approximately 24 h oscillators that temporally regulate many physiological and behavioural processes. In order to be beneficial for the organism, these clocks must be synchronized with the environmental cycles on a daily basis. Both light : dark and the concomitant daily temperature cycles (TCs) function as Zeitgeber (‘time giver’) and efficiently entrain circadian clocks. The temperature receptors mediating this synchronization have not been identified. Transient receptor potential (TRP) channels function as thermo-receptors in animals, and here we show that the Pyrexia (Pyx) TRP channel mediates temperature synchronization in Drosophila melanogaster . Pyx is expressed in peripheral sensory organs (chordotonal organs), which previously have been implicated in temperature synchronization. Flies deficient for Pyx function fail to synchronize their behaviour to TCs in the lower range (16–20°C), and this deficit can be partially rescued by introducing a wild-type copy of the pyx gene. Synchronization to higher TCs is not affected, demonstrating a specific role for Pyx at lower temperatures. In addition, pyx mutants speed up their clock after being exposed to TCs. Our results identify the first TRP channel involved in temperature synchronization of circadian clocks.
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Duitama, Milena, Yurany Moreno, Sandra Paola Santander, Zulma Casas, Jhon Jairo Sutachan, Yolima P. Torres et Sonia L. Albarracín. « TRP Channels as Molecular Targets to Relieve Cancer Pain ». Biomolecules 12, no 1 (21 décembre 2021) : 1. http://dx.doi.org/10.3390/biom12010001.
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Transient receptor potential (TRP) channels are critical receptors in the transduction of nociceptive stimuli. The microenvironment of diverse types of cancer releases substances, including growth factors, neurotransmitters, and inflammatory mediators, which modulate the activity of TRPs through the regulation of intracellular signaling pathways. The modulation of TRP channels is associated with the peripheral sensitization observed in patients with cancer, which results in mild noxious sensory stimuli being perceived as hyperalgesia and allodynia. Secondary metabolites derived from plant extracts can induce the activation, blocking, and desensitization of TRP channels. Thus, these compounds could act as potential therapeutic agents, as their antinociceptive properties could be beneficial in relieving cancer-derived pain. In this review, we will summarize the role of TRPV1 and TRPA1 in pain associated with cancer and discuss molecules that have been reported to modulate these channels, focusing particularly on the mechanisms of channel activation associated with molecules released in the tumor microenvironment.
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Lamas, J. Antonio, Lola Rueda-Ruzafa et Salvador Herrera-Pérez. « Ion Channels and Thermosensitivity : TRP, TREK, or Both ? » International Journal of Molecular Sciences 20, no 10 (14 mai 2019) : 2371. http://dx.doi.org/10.3390/ijms20102371.
Texte intégralRésumé :
Controlling body temperature is a matter of life or death for most animals, and in mammals the complex thermoregulatory system is comprised of thermoreceptors, thermosensors, and effectors. The activity of thermoreceptors and thermoeffectors has been studied for many years, yet only recently have we begun to obtain a clear picture of the thermosensors and the molecular mechanisms involved in thermosensory reception. An important step in this direction was the discovery of the thermosensitive transient receptor potential (TRP) cationic channels, some of which are activated by increases in temperature and others by a drop in temperature, potentially converting the cells in which they are expressed into heat and cold receptors. More recently, the TWIK-related potassium (TREK) channels were seen to be strongly activated by increases in temperature. Hence, in this review we want to assess the hypothesis that both these groups of channels can collaborate, possibly along with other channels, to generate the wide range of thermal sensations that the nervous system is capable of handling.
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Tóth, G., A. Keresztes, Cs Tömböly, A. Péter, F. Fülöp, D. Tourwé, E. Navratilova et al. « New endomorphin analogs with mu-agonist and delta-antagonist properties ». Pure and Applied Chemistry 76, no 5 (1 janvier 2004) : 951–57. http://dx.doi.org/10.1351/pac200476050951.
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Endomorphins (endomorphin-1,H-Tyr-Pro-Trp-Phe-NH 2 ,endomorphin-2, Tyr-Pro-Phe-Phe-NH2) are potent and selective µ-opioid receptor agonists. In order to improve the affinity and chemical stability of endomorphins, we have designed, synthesized, and characterized novel analogs with unnatural (2 ',6 '-dimethyltyrosine, Dmt) and/or ß-alicyclic amino acids (ACPC and ACHC). Radioligand binding assay indicated that several of the novel analogs exhibit high affinity for both µ-and d-opioid receptors in rat-or mouse-brain membrane preparations. The most promising derivatives—such as Dmt-Pro-Trp/Phe-Phe-NH2, Dmt-(1 S,2R)-ACPC-Phe-Phe-NH2, and Dmt-(1S,2R)-ACHC-Phe-Phe-NH2 )—were characterized in recombinant cell lines expressing human µ-or d-opioid receptors. Interestingly, while these novel peptides were potent opioid agonists in the functional [35S]GTPgammaS binding assays in Chinese hamster ovary cells expressing the µ-opioid receptors, some behaved as antagonist or inverse agonist in the human d-opioid receptor-expressing CHO cells. Since it has previously been demonstrated that the coadministration of d-antagonists with µ-analgesics attenuates the development of analgesic tolerance, introduction of high-affinity d-antagonist properties into the µ-agonist endomorphins is expected to lead to potent analgesics that produce limited tolerance.
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Cawston, Erin E., Kaleeckal G. Harikumar et Laurence J. Miller. « Ligand-induced internalization of the type 1 cholecystokinin receptor independent of recognized signaling activity ». American Journal of Physiology-Cell Physiology 302, no 3 (février 2012) : C615—C627. http://dx.doi.org/10.1152/ajpcell.00193.2011.
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Receptor ligands, identified as antagonists, based on the absence of stimulation of signaling, can rarely stimulate receptor internalization. d-Tyr-Gly-[(Nle28,31,d-Trp30)CCK-26–32]-2-phenylethyl ester (d-Trp-OPE) is such a ligand that binds to the cholecystokinin (CCK) receptor and stimulates internalization. Here, the molecular basis of this trafficking event is explored, with the assumption that ligand binding initiates conformational change, exposing an epitope to direct endocytosis. Ligand-stimulated internalization was studied morphologically using fluorescent CCK and d-Trp-OPE. d-Trp-OPE occupation of Chinese hamster ovary cell receptors stimulated internalization into the same region as CCK. Arrestin-biased action was ruled out using morphological translocation of fluorescent arrestin 2 and arrestin 3, moving to the membrane in response to CCK, but not d-Trp-OPE. Possible roles of the carboxyl terminus were studied using truncated receptor constructs, eliminating the proline-rich distal tail, the serine/threonine-rich midregion, and the remainder to the vicinal cysteines. None of these constructs disrupted d-Trp-OPE-stimulated internalization. Possible contributions of transmembrane segments were studied using competitive inhibition with peptides that also had no effect. Intracellular regions were studied with a similar strategy using coexpressing cell lines. Peptides corresponding to ends of each loop region were studied, with only the peptide at the carboxyl end of the third loop inhibiting d-Trp-OPE-stimulated internalization but having no effect on CCK-stimulated internalization. The region contributing to this effect was refined to peptide 309–323, located below the recognized G protein-association motif. While a receptor in which this segment was deleted did internalize in response to d-Trp-OPE, it exhibited abnormal ligand binding and did not signal in response to CCK, suggesting an abnormal conformation and possible mechanism of internalization distinct from that being studied. This interpretation was further supported by the inability of peptide 309–323 to inhibit its d-Trp-OPE-stimulated internalization. Thus the 309–323 region of the type 1 CCK receptor affects antagonist-stimulated internalization of this receptor, although its mechanism and interacting partner are not yet clear.
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Zubare-Samuelov, Meirav, Irena Peri, Michael Tal, Mark Tarshish, Andrew I. Spielman et Michael Naim. « Some sweet and bitter tastants stimulate inhibitory pathway of adenylyl cyclase via melatonin and α2-adrenergic receptors in Xenopus laevis melanophores ». American Journal of Physiology-Cell Physiology 285, no 5 (novembre 2003) : C1255—C1262. http://dx.doi.org/10.1152/ajpcell.00149.2003.
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The sweeteners saccharin, d-tryptophan, and neohesperidin dihydrochalcone (NHD) and the bitter tastant cyclo(Leu-Trp) stimulated concentration-dependent pigment aggregation in a Xenopus laevis melanophore cell line similar to melatonin. Like melatonin, these tastants inhibited (by 45-92%) cAMP formation in melanophores; pertussis toxin pretreatment almost completely abolished the tastant-induced cAMP inhibition, suggesting the involvement of the inhibitory pathway (Gi) of adenylyl cyclase. The presence of luzindole (melatonin receptor antagonist) almost completely abolished the inhibition of cAMP formation induced by saccharin, d-tryptophan, and cyclo(Leu-Trp) but only slightly affected the inhibitory effect of NHD. In contrast, the presence of an α2-adrenergic receptor antagonist, yohimbine, almost completely abolished the inhibition of cAMP formation induced by NHD but had only a minor effect on that induced by the other tastants. Thus saccharin, d-tryptophan, and cyclo(Leu-Trp) are melatonin receptor agonists whereas NHD is an α2-adrenergic receptor agonist, but both pathways lead to the same transduction output and cellular response. Formation of d- myo-inositol 1,4,5-trisphosphate (IP3) in melanophores was reduced (15-58%, no concentration dependence) by saccharin, d-tryptophan, and cyclo(Leu-Trp) stimulation but increased by NHD stimulation. Tastant stimulation did not affect cGMP. Although some of the above tastants were found to be membrane permeant, their direct activation of downstream transduction components in this experimental system is questionable. MT1 and MT2 melatonin receptor mRNAs were identified in rat circumvallate papilla taste buds and nonsensory epithelium, suggesting the occurrence of MT1 and MT2 receptors in these tissues. Melatonin stimulation reduced the cellular content of cAMP in taste cells, which may or may not be related to taste sensation.
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Koyama, Sachiko, et Thomas Heinbockel. « The Effects of Essential Oils and Terpenes in Relation to Their Routes of Intake and Application ». International Journal of Molecular Sciences 21, no 5 (25 février 2020) : 1558. http://dx.doi.org/10.3390/ijms21051558.
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Essential oils have been used in multiple ways, i.e., inhaling, topically applying on the skin, and drinking. Thus, there are three major routes of intake or application involved: the olfactory system, the skin, and the gastro-intestinal system. Understanding these routes is important for clarifying the mechanisms of action of essential oils. Here we summarize the three systems involved, and the effects of essential oils and their constituents at the cellular and systems level. Many factors affect the rate of uptake of each chemical constituent included in essential oils. It is important to determine how much of each constituent is included in an essential oil and to use single chemical compounds to precisely test their effects. Studies have shown synergistic influences of the constituents, which affect the mechanisms of action of the essential oil constituents. For the skin and digestive system, the chemical components of essential oils can directly activate gamma aminobutyric acid (GABA) receptors and transient receptor potential channels (TRP) channels, whereas in the olfactory system, chemical components activate olfactory receptors. Here, GABA receptors and TRP channels could play a role, mostly when the signals are transferred to the olfactory bulb and the brain.
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Zholos, Alexander V., Andrey A. Zholos et Thomas B. Bolton. « G-protein–gated TRP-like Cationic Channel Activated by Muscarinic Receptors ». Journal of General Physiology 123, no 5 (26 avril 2004) : 581–98. http://dx.doi.org/10.1085/jgp.200309002.
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There is little information about the mechanisms by which G-protein–coupled receptors gate ion channels although many ionotropic receptors are well studied. We have investigated gating of the muscarinic cationic channel, which mediates the excitatory effect of acetylcholine in smooth muscles, and proposed a scheme consisting of four pairs of closed and open states. Channel kinetics appeared to be the same in cell-attached or outside-out patches whether the channel was activated by carbachol application or by intracellular dialysis with GTPγS. Since in the latter case G-proteins are permanently active, it is concluded that the cationic channel is the major determinant of its own gating, similarly to the KACh channel (Ivanova-Nikolova, T.T., and G.E. Breitwieser. 1997. J. Gen. Physiol. 109:245–253). Analysis of adjacent-state dwell times revealed connections between the states that showed features conserved among many other ligand-gated ion channels (e.g., nAChR, BKCa channel). Open probability (PO) of the cationic channel was increased by membrane depolarization consistent with the prominent U-shaped I-V relationship of the muscarinic whole-cell current at negative potentials. Membrane potential affected transitions within each closed-open state pair but had little effect on transitions between pairs; thus, the latter are likely to be caused by interactions of the channel with its ligands, e.g., Ca2+ and Gαo-GTP. Channel activity was highly heterogeneous, as was evident from the prominent cycling behavior when PO was measured over 5-s intervals. This was related to the variable frequency of openings (as in the KACh channel) and, especially, to the number of long openings between consecutive long shuttings. Analysis of the underlying Markov chain in terms of probabilities allowed us to evaluate the contribution of each open state to the integral current (from shortest to longest open state: 0.1, 3, 24, and 73%) as PO increased 525-fold in three stages.
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Gutorov, Rita, Ben Katz, Elisheva Rhodes-Mordov, Rachel Zaguri, Tal Brandwine-Shemmer et Baruch Minke. « The Role of Membrane Lipids in Light-Activation of Drosophila TRP Channels ». Biomolecules 12, no 3 (28 février 2022) : 382. http://dx.doi.org/10.3390/biom12030382.
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Transient Receptor Potential (TRP) channels constitute a large superfamily of polymodal channel proteins with diverse roles in many physiological and sensory systems that function both as ionotropic and metabotropic receptors. From the early days of TRP channel discovery, membrane lipids were suggested to play a fundamental role in channel activation and regulation. A prominent example is the Drosophila TRP and TRP-like (TRPL) channels, which are predominantly expressed in the visual system of Drosophila. Light activation of the TRP and TRPL channels, the founding members of the TRP channel superfamily, requires activation of phospholipase Cβ (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into Diacylglycerol (DAG) and Inositol 1, 4,5-trisphosphate (IP3). However, the events required for channel gating downstream of PLC activation are still under debate and led to several hypotheses regarding the mechanisms by which lipids gate the channels. Despite many efforts, compelling evidence of the involvement of DAG accumulation, PIP2 depletion or IP3-mediated Ca2+ release in light activation of the TRP/TRPL channels are still lacking. Exogeneous application of poly unsaturated fatty acids (PUFAs), a product of DAG hydrolysis was demonstrated as an efficient way to activate the Drosophila TRP/TRPL channels. However, compelling evidence for the involvement of PUFAs in physiological light-activation of the TRP/TRPL channels is still lacking. Light-induced mechanical force generation was measured in photoreceptor cells prior to channel opening. This mechanical force depends on PLC activity, suggesting that the enzymatic activity of PLC converting PIP2 into DAG generates membrane tension, leading to mechanical gating of the channels. In this review, we will present the roles of membrane lipids in light activation of Drosophila TRP channels and present the many advantages of this model system in the exploration of TRP channel activation under physiological conditions.
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Gudermann, Thomas, Alexander Dietrich et Hermann Kalwa. « TRPC channels in vascular cell function ». Thrombosis and Haemostasis 103, no 02 (2010) : 262–70. http://dx.doi.org/10.1160/th09-08-0517.
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SummaryThe mammalian transient receptor potential (TRP) superfamily of non-selective cation channels can be divided into six major families. Among them, the “classical” or “canonical” TRPC family is most closely related to Drosophila TRP, the founding member of the superfamily. All seven channels of this family designated TRPC1–7 share the common property of receptor-operated activation through phospholipase C (PLC)-coupled receptors, but their regulation by store-dependent mechanisms involving the proteins STIM and ORAi is still discussed controversially. This review will focus on the proposed functions of TRPC proteins in cells of the vascular system (e.g. platelets, smooth muscle cells and endothelial cells) and will present data concerning their physiological functions analysed in isolated tissues with down-regulated channel activity and in gene-deficient mouse models.
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Liu, Beiying, et Feng Qin. « The Xenopus tropicalis orthologue of TRPV3 is heat sensitive ». Journal of General Physiology 146, no 5 (12 octobre 2015) : 411–21. http://dx.doi.org/10.1085/jgp.201511454.
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Thermosensitive members of the transient receptor potential (TRP) family of ion channels (thermal TRP channels) play a crucial role in mammalian temperature sensing. Orthologues of these channels are present in lower vertebrates and, remarkably, some thermal TRP orthologues from different species appear to mediate opposing responses to temperature. For example, whereas the mammalian TRPV3 channel is activated by heat, frog TRPV3 is reportedly activated by cold. Intrigued by the potential implications of these opposing responses to temperature for the mechanism of temperature-dependent gating, we cloned Xenopus laevis TRPV3 and functionally expressed it in both mammalian cell lines and Xenopus oocytes. We found that, when expressed in mammalian cells, the recombinant channel lacks the reported cold sensitivity; rather, it is activated by temperatures >50°C. Furthermore, when expressed in mammalian cells, the frog orthologue shows other features characteristic of mammalian TRPV3, including activation by the agonist 2-aminoethoxydiphenyl borate and an increased response with repeated stimulation. We detected both heat- and cold-activated currents in Xenopus oocytes expressing the recombinant frog TRPV3 channel. However, cold-activated currents were also apparent in control oocytes lacking recombinant TRPV3. Our data indicate that frog TRPV3 resembles its mammalian orthologues in terms of its thermosensitivity and is intrinsically activated by heat. Thus, all known vanilloid receptors are activated by heat. Our data also show that Xenopus oocytes contain endogenous receptors that are activated by cold, and suggest that cold sensitivity of TRP channels established using Xenopus oocytes as a functional expression system may need to be revisited.
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Brice-Tutt, Ariana C., Sanjeewa N. Senadheera, Michelle L. Ganno, Shainnel O. Eans, Tanvir Khaliq, Thomas F. Murray, Jay P. McLaughlin et Jane V. Aldrich. « Phenylalanine Stereoisomers of CJ-15,208 and [d-Trp]CJ-15,208 Exhibit Distinctly Different Opioid Activity Profiles ». Molecules 25, no 17 (2 septembre 2020) : 3999. http://dx.doi.org/10.3390/molecules25173999.
Texte intégralRésumé :
The macrocyclic tetrapeptide cyclo[Phe-d-Pro-Phe-Trp] (CJ-15,208) and its stereoisomer cyclo[Phe-d-Pro-Phe-d-Trp] exhibit different opioid activity profiles in vivo. The present study evaluated the influence of the Phe residues’ stereochemistry on the peptides’ opioid activity. Five stereoisomers were synthesized by a combination of solid-phase peptide synthesis and cyclization in solution. The analogs were evaluated in vitro for opioid receptor affinity in radioligand competition binding assays, and for opioid activity and selectivity in vivo in the mouse 55 °C warm-water tail-withdrawal assay. Potential liabilities of locomotor impairment, respiratory depression, acute tolerance development, and place conditioning were also assessed in vivo. All of the stereoisomers exhibited antinociception following either intracerebroventricular or oral administration differentially mediated by multiple opioid receptors, with kappa opioid receptor (KOR) activity contributing for all of the peptides. However, unlike the parent peptides, KOR antagonism was exhibited by only one stereoisomer, while another isomer produced DOR antagonism. The stereoisomers of CJ-15,208 lacked significant respiratory effects, while the [d-Trp]CJ-15,208 stereoisomers did not elicit antinociceptive tolerance. Two isomers, cyclo[d-Phe-d-Pro-d-Phe-Trp] (3) and cyclo[Phe-d-Pro-d-Phe-d-Trp] (5), did not elicit either preference or aversion in a conditioned place preference assay. Collectively, these stereoisomers represent new lead compounds for further investigation in the development of safer opioid analgesics.
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Zhu, Fei, Guanxing Yang, Manivannan Kalavathi Dhinakaran, Rui Wang, Miaomiao Song et Haibing Li. « A pyrophosphate-activated nanochannel inspired by a TRP ion channel ». Chemical Communications 55, no 85 (2019) : 12833–36. http://dx.doi.org/10.1039/c9cc06615b.
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Chiesa, Mariella Della, Simona Carlomagno, Guido Frumento, Mirna Balsamo, Claudia Cantoni, Romana Conte, Lorenzo Moretta, Alessandro Moretta et Massimo Vitale. « The tryptophan catabolite l-kynurenine inhibits the surface expression of NKp46- and NKG2D-activating receptors and regulates NK-cell function ». Blood 108, no 13 (15 décembre 2006) : 4118–25. http://dx.doi.org/10.1182/blood-2006-03-006700.
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Abstract Tryptophan (Trp) catabolism mediated by indoleamine 2,3-dioxygenase (IDO) plays a central role in the regulation of T-cell–mediated immune responses. In this study, we also demonstrate that natural killer (NK)–cell function can be influenced by IDO. Indeed, l-kynurenine, a Trp-derived catabolite resulting from IDO activity, was found to prevent the cytokine-mediated up-regulation of the expression and function of specific triggering receptors responsible for the induction of NK-cell–mediated killing. The effect of l-kynurenine appears to be restricted to NKp46 and NKG2D, while it does not affect other surface receptors such as NKp30 or CD16. As a consequence, l-kynurenine–treated NK cells display impaired ability to kill target cells recognized via NKp46 and NKG2D. Instead, they maintain the ability to kill targets, such as dendritic cells (DCs), that are mainly recognized via the NKp30 receptor. The effect of l-kynurenine, which is effective at both the transcriptional and the protein level, can be reverted, since NK cells were found to recover their functional competence after washing.
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Goodarzi, Parniyan, Mohammad Habibi, Kennedy Roberts, Julia Sutton, Cedrick Ndhumba Shili, Dingbo Lin et Adel Pezeshki. « Dietary Tryptophan Supplementation Alters Fat and Glucose Metabolism in a Low-Birthweight Piglet Model ». Nutrients 13, no 8 (26 juillet 2021) : 2561. http://dx.doi.org/10.3390/nu13082561.
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Low birthweight (LBW) is associated with metabolic complications, such as glucose and lipid metabolism disturbances in early life. The objective of this study was to assess: (1) the effect of dietary tryptophan (Trp) on glucose and fat metabolism in an LBW piglet model, and (2) the role peripheral 5-hydroxytryptamine type 3 (5HT3) receptors in regulating the feeding behavior in LBW piglets fed with Trp-supplemented diets. Seven-day-old piglets were assigned to 4 treatments: normal birthweight-0%Trp (NBW-T0), LBW-0%Trp (LBW-T0), LBW-0.4%Trp (LBW-T0.4), and LBW-0.8%Trp (LBW-T0.8) for 3 weeks. Compared to LBW-T0, the blood glucose was decreased in LBW-T0.8 at 60 min following the meal test, and the triglycerides were lower in LBW-T0.4 and LBW-T0.8. Relative to LBW-T0, LBW-T0.8 had a lower transcript and protein abundance of hepatic glucose transporter-2, a higher mRNA abundance of glucokinase, and a lower transcript of phosphoenolpyruvate carboxykinase. LBW-T0.4 tended to have a lower protein abundance of sodium-glucose co-transporter 1 in the jejunum. In comparison with LBW-T0, LBW-T0.4 and LBW-T0.8 had a lower transcript of hepatic acetyl-CoA carboxylase, and LBW-T0.4 had a higher transcript of 3-hydroxyacyl-CoA dehydrogenase. Blocking 5-HT3 receptors with ondansetron reduced the feed intake in all groups, with a transient effect on LBW-T0, but more persistent effect on LBW-T0.8 and NBW-T0. In conclusion, Trp supplementation reduced the hepatic lipogenesis and gluconeogenesis, but increased the glycolysis in LBW piglets. Peripheral serotonin is likely involved in the regulation of feeding behavior, particularly in LBW piglets fed diets supplemented with a higher dose of Trp.
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Rapoport, AP, S. Luhowskyj, P. Doshi et JF DiPersio. « Mutational analysis of the alpha subunit of the human interleukin-3 receptor ». Blood 87, no 1 (1 janvier 1996) : 112–22. http://dx.doi.org/10.1182/blood.v87.1.112.112.
Texte intégralRésumé :
Abstract The alpha subunit of the human interleukin-3 receptor (IL-3R alpha) is a 70-kD glycoprotein member of the hematopoietin receptor superfamily. This protein associates with a beta subunit common to the receptors for IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) to form a high-affinity receptor for IL-3. To identify regions of IL-3R alpha critical for ligand binding and receptor function, cDNAs encoding mutant receptors were generated and expressed in COS cells along with the beta subunit. Mutant receptors lacking almost the entire cytoplasmic domain of IL-3R alpha [IL-3R alpha(CD)] or carrying a substitution of trp for leu in the membrane proximal leu-ser-x-trp-ser (LSXWS) box bound 125I-IL-3 with nearly the same affinity as wild-type IL-3R alpha. In contrast, a mutant lacking the entire “LSXWS” motif failed to bind 125I-IL-3 with high affinity despite showing surface expression. In addition, hybrid receptors composed of the first 104 amino acids (aa) of IL-3R alpha joined to aa 118 through 400 of the alpha subunit of the GM-CSF receptor (GM-R alpha) [IL-3R alpha/GM-R alpha] or the first 118 aa of GM-R alpha joined to aa 104 through 378 of IL-3R alpha [GM-R alpha/IL-3R alpha] failed to bind 125I-IL-3 in the presence of the beta subunit. A third hybrid receptor composed of the first 281 residues of IL-3R alpha fused to residues 306 through 379 of GM-R alpha [IL-3R alpha/GM-R alpha-DS] also failed to bind 125I-IL-3 in the presence of the beta subunit but, in contrast to the IL-3R alpha/GM- R alpha hybrid, demonstrated weak surface expression. Mutant receptors lacking the N-terminal 30 aa and the N-terminal 9 aa also did not bind 125I-IL-3 with high affinity, although both were expressed on the cell surface. These data suggest that although the cytoplasmic domain and the leucine residue of the “LSXWS” box are not critical for ligand binding or beta-subunit association, the “LSXWS” motif and amino-terminal sequences are important for these functions.
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Rapoport, AP, S. Luhowskyj, P. Doshi et JF DiPersio. « Mutational analysis of the alpha subunit of the human interleukin-3 receptor ». Blood 87, no 1 (1 janvier 1996) : 112–22. http://dx.doi.org/10.1182/blood.v87.1.112.bloodjournal871112.
Texte intégralRésumé :
The alpha subunit of the human interleukin-3 receptor (IL-3R alpha) is a 70-kD glycoprotein member of the hematopoietin receptor superfamily. This protein associates with a beta subunit common to the receptors for IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) to form a high-affinity receptor for IL-3. To identify regions of IL-3R alpha critical for ligand binding and receptor function, cDNAs encoding mutant receptors were generated and expressed in COS cells along with the beta subunit. Mutant receptors lacking almost the entire cytoplasmic domain of IL-3R alpha [IL-3R alpha(CD)] or carrying a substitution of trp for leu in the membrane proximal leu-ser-x-trp-ser (LSXWS) box bound 125I-IL-3 with nearly the same affinity as wild-type IL-3R alpha. In contrast, a mutant lacking the entire “LSXWS” motif failed to bind 125I-IL-3 with high affinity despite showing surface expression. In addition, hybrid receptors composed of the first 104 amino acids (aa) of IL-3R alpha joined to aa 118 through 400 of the alpha subunit of the GM-CSF receptor (GM-R alpha) [IL-3R alpha/GM-R alpha] or the first 118 aa of GM-R alpha joined to aa 104 through 378 of IL-3R alpha [GM-R alpha/IL-3R alpha] failed to bind 125I-IL-3 in the presence of the beta subunit. A third hybrid receptor composed of the first 281 residues of IL-3R alpha fused to residues 306 through 379 of GM-R alpha [IL-3R alpha/GM-R alpha-DS] also failed to bind 125I-IL-3 in the presence of the beta subunit but, in contrast to the IL-3R alpha/GM- R alpha hybrid, demonstrated weak surface expression. Mutant receptors lacking the N-terminal 30 aa and the N-terminal 9 aa also did not bind 125I-IL-3 with high affinity, although both were expressed on the cell surface. These data suggest that although the cytoplasmic domain and the leucine residue of the “LSXWS” box are not critical for ligand binding or beta-subunit association, the “LSXWS” motif and amino-terminal sequences are important for these functions.
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Narayanan, Damodaran, Adebowale Adebiyi et Jonathan H. Jaggar. « Inositol trisphosphate receptors in smooth muscle cells ». American Journal of Physiology-Heart and Circulatory Physiology 302, no 11 (1 juin 2012) : H2190—H2210. http://dx.doi.org/10.1152/ajpheart.01146.2011.
Texte intégralRésumé :
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are a family of tetrameric intracellular calcium (Ca2+) release channels that are located on the sarcoplasmic reticulum (SR) membrane of virtually all mammalian cell types, including smooth muscle cells (SMC). Here, we have reviewed literature investigating IP3R expression, cellular localization, tissue distribution, activity regulation, communication with ion channels and organelles, generation of Ca2+ signals, modulation of physiological functions, and alterations in pathologies in SMCs. Three IP3R isoforms have been identified, with relative expression and cellular localization of each contributing to signaling differences in diverse SMC types. Several endogenous ligands, kinases, proteins, and other modulators control SMC IP3R channel activity. SMC IP3Rs communicate with nearby ryanodine-sensitive Ca2+ channels and mitochondria to influence SR Ca2+ release and reactive oxygen species generation. IP3R-mediated Ca2+ release can stimulate plasma membrane-localized channels, including transient receptor potential (TRP) channels and store-operated Ca2+ channels. SMC IP3Rs also signal to other proteins via SR Ca2+ release-independent mechanisms through physical coupling to TRP channels and local communication with large-conductance Ca2+-activated potassium channels. IP3R-mediated Ca2+ release generates a wide variety of intracellular Ca2+ signals, which vary with respect to frequency, amplitude, spatial, and temporal properties. IP3R signaling controls multiple SMC functions, including contraction, gene expression, migration, and proliferation. IP3R expression and cellular signaling are altered in several SMC diseases, notably asthma, atherosclerosis, diabetes, and hypertension. In summary, IP3R-mediated pathways control diverse SMC physiological functions, with pathological alterations in IP3R signaling contributing to disease.
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Hossain, Mohammad, Marina Bakri, Farhana Yahya, Hiroshi Ando, Shumpei Unno et Junichi Kitagawa. « The Role of Transient Receptor Potential (TRP) Channels in the Transduction of Dental Pain ». International Journal of Molecular Sciences 20, no 3 (27 janvier 2019) : 526. http://dx.doi.org/10.3390/ijms20030526.
Texte intégralRésumé :
Dental pain is a common health problem that negatively impacts the activities of daily living. Dentine hypersensitivity and pulpitis-associated pain are among the most common types of dental pain. Patients with these conditions feel pain upon exposure of the affected tooth to various external stimuli. However, the molecular mechanisms underlying dental pain, especially the transduction of external stimuli to electrical signals in the nerve, remain unclear. Numerous ion channels and receptors localized in the dental primary afferent neurons (DPAs) and odontoblasts have been implicated in the transduction of dental pain, and functional expression of various polymodal transient receptor potential (TRP) channels has been detected in DPAs and odontoblasts. External stimuli-induced dentinal tubular fluid movement can activate TRP channels on DPAs and odontoblasts. The odontoblasts can in turn activate the DPAs by paracrine signaling through ATP and glutamate release. In pulpitis, inflammatory mediators may sensitize the DPAs. They could also induce post-translational modifications of TRP channels, increase trafficking of these channels to nerve terminals, and increase the sensitivity of these channels to stimuli. Additionally, in caries-induced pulpitis, bacterial products can directly activate TRP channels on DPAs. In this review, we provide an overview of the TRP channels expressed in the various tooth structures, and we discuss their involvement in the development of dental pain.
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Denis, Valérie, et Martha S. Cyert. « Internal Ca2+ release in yeast is triggered by hypertonic shock and mediated by a TRP channel homologue ». Journal of Cell Biology 156, no 1 (7 janvier 2002) : 29–34. http://dx.doi.org/10.1083/jcb.200111004.
Texte intégralRésumé :
Calcium ions, present inside all eukaryotic cells, are important second messengers in the transduction of biological signals. In mammalian cells, the release of Ca2+ from intracellular compartments is required for signaling and involves the regulated opening of ryanodine and inositol-1,4,5-trisphosphate (IP3) receptors. However, in budding yeast, no signaling pathway has been shown to involve Ca2+ release from internal stores, and no homologues of ryanodine or IP3 receptors exist in the genome. Here we show that hyperosmotic shock provokes a transient increase in cytosolic Ca2+ in vivo. Vacuolar Ca2+, which is the major intracellular Ca2+ store in yeast, is required for this response, whereas extracellular Ca2+ is not. We aimed to identify the channel responsible for this regulated vacuolar Ca2+ release. Here we report that Yvc1p, a vacuolar membrane protein with homology to transient receptor potential (TRP) channels, mediates the hyperosmolarity induced Ca2+ release. After this release, low cytosolic Ca2+ is restored and vacuolar Ca2+ is replenished through the activity of Vcx1p, a Ca2+/H+ exchanger. These studies reveal a novel mechanism of internal Ca2+ release and establish a new function for TRP channels.
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Stasiłowicz, Anna, Anna Tomala, Irma Podolak et Judyta Cielecka-Piontek. « Cannabis sativa L. as a Natural Drug Meeting the Criteria of a Multitarget Approach to Treatment ». International Journal of Molecular Sciences 22, no 2 (14 janvier 2021) : 778. http://dx.doi.org/10.3390/ijms22020778.
Texte intégralRésumé :
Cannabis sativa L. turned out to be a valuable source of chemical compounds of various structures, showing pharmacological activity. The most important groups of compounds include phytocannabinoids and terpenes. The pharmacological activity of Cannabis (in epilepsy, sclerosis multiplex (SM), vomiting and nausea, pain, appetite loss, inflammatory bowel diseases (IBDs), Parkinson’s disease, Tourette’s syndrome, schizophrenia, glaucoma, and coronavirus disease 2019 (COVID-19)), which has been proven so far, results from the affinity of these compounds predominantly for the receptors of the endocannabinoid system (the cannabinoid receptor type 1 (CB1), type two (CB2), and the G protein-coupled receptor 55 (GPR55)) but, also, for peroxisome proliferator-activated receptor (PPAR), glycine receptors, serotonin receptors (5-HT), transient receptor potential channels (TRP), and GPR, opioid receptors. The synergism of action of phytochemicals present in Cannabis sp. raw material is also expressed in their increased bioavailability and penetration through the blood–brain barrier. This review provides an overview of phytochemistry and pharmacology of compounds present in Cannabis extracts in the context of the current knowledge about their synergistic actions and the implications of clinical use in the treatment of selected diseases.
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Valencia-Guzmán, Christian J., Jesús E. Castro-Ruiz, Teresa García-Gasca, Alejandra Rojas-Molina, Antonio Romo-Mancillas, Francisco J. Luna-Vázquez, Juana I. Rojas-Molina et César Ibarra-Alvarado. « Endothelial TRP channels and cannabinoid receptors are involved in affinin-induced vasodilation ». Fitoterapia 153 (septembre 2021) : 104985. http://dx.doi.org/10.1016/j.fitote.2021.104985.
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Thermos, K., M. D. Meglasson, J. Nelson, K. M. Lounsbury et T. Reisine. « Pancreatic beta-cell somatostatin receptors ». American Journal of Physiology-Endocrinology and Metabolism 259, no 2 (1 août 1990) : E216—E224. http://dx.doi.org/10.1152/ajpendo.1990.259.2.e216.
Texte intégralRésumé :
The characteristics of somatostatin (SRIF) receptors in rat pancreatic beta-cells were investigated using rat islets and the beta-cell line HIT-T15 (HIT). The biochemical properties of the SRIF receptors were examined with 125I-labeled des-Ala-1,Gly-2-desamino-Cys-3-[Tyr-11]- dicarba3,14-somatostatin (CGP 23996). 125I-CGP 23996 bound to SRIF receptors in HIT cells with high affinity and in a saturable manner. The binding of 125I-CGP 23996 to SRIF receptors was blocked by SRIF analogues with a rank order of potency of somatostatin 28 (SRIF-28) greater than D-Trp-8-somatostatin greater than somatostatin 14 (SRIF-14). To investigate the physical properties of the HIT cell SRIF receptor, the receptor was covalently labeled with 125I-CGP 23996 using photo-cross-linking techniques. 125I-CGP 23996 specifically labeled a protein of 55 kDa in HIT cell membranes. The size of the SRIF receptor in HIT cells is similar to the size of the SRIF receptor labeled with 125I-CGP 23996 in membranes of freshly isolated islets, suggesting that the physical properties of SRIF receptors in HIT cells and rat islet cells are similar. The binding studies suggest that beta-cells predominantly express a SRIF-28-preferring receptor. In freshly isolated islets, glucose- and arginine-stimulated insulin release was effectively blocked by SRIF-28 but not by SRIF-14. SRIF-14 did inhibit arginine-stimulated glucagon secretion from freshly isolated islets. The dissociation of the inhibitory effects of SRIF-28 and SRIF-14 on insulin and glucagon release from freshly isolated islets suggests that the two peptides act through different receptors in islets to regulate hormone secretion.
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Reeh, Peter W., et Michael J. M. Fischer. « Nobel somatosensations and pain ». Pflügers Archiv - European Journal of Physiology 474, no 4 (14 février 2022) : 405–20. http://dx.doi.org/10.1007/s00424-022-02667-x.
Texte intégralRésumé :
AbstractThe Nobel prices 2021 for Physiology and Medicine have been awarded to David Julius and Ardem Patapoutian "for their discoveries of receptors for temperature and touch", TRPV1 and PIEZO1/2. The present review tells the past history of the capsaicin receptor, covers further selected TRP channels, TRPA1 in particular, and deals with mechanosensitivity in general and mechanical hyperalgesia in particular. Other achievements of the laureates and translational aspects of their work are shortly treated.
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Diaz-Franulic, Ignacio, Christian Verdugo, Felipe Gonzalez, Fernando Gonzalez-Nilo et Ramon Latorre. « Thermodynamic and structural basis of temperature-dependent gating in TRP channels ». Biochemical Society Transactions 49, no 5 (8 octobre 2021) : 2211–19. http://dx.doi.org/10.1042/bst20210301.
Texte intégralRésumé :
Living organisms require detecting the environmental thermal clues for survival, allowing them to avoid noxious stimuli or find prey moving in the dark. In mammals, the Transient Receptor Potential ion channels superfamily is constituted by 27 polymodal receptors whose activity is controlled by small ligands, peptide toxins, protons and voltage. The thermoTRP channels subgroup exhibits unparalleled temperature dependence -behaving as heat and cold sensors. Functional studies have dissected their biophysical features in detail, and the advances of single-particle Cryogenic Electron microscopy provided the structural framework required to propose detailed channel gating mechanisms. However, merging structural and functional evidence for temperature-driven gating of thermoTRP channels has been a hard nut to crack, remaining an open question nowadays. Here we revisit the highlights on the study of heat and cold sensing in thermoTRP channels in the light of the structural data that has emerged during recent years.