Journal articles on the topic 'Dopamine'
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1
Helms, My N., Xi-Juan Chen, Semra Ramosevac, Douglas C. Eaton, and Lucky Jain. "Dopamine regulation of amiloride-sensitive sodium channels in lung cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 290, no. 4 (April 2006): L710—L722. http://dx.doi.org/10.1152/ajplung.00486.2004.
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Dopamine increases lung fluid clearance. This is partly due to activation of basolateral Na-K-ATPase. However, activation of Na-K-ATPase by itself is unlikely to produce large changes in transepithelial transport. Therefore, we examined apical and basolateral dopamine's effect on apical, highly selective sodium channels [epithelial sodium channels (ENaC)] in monolayers of an alveolar type 2 cell line (L2). Dopamine increased channel open probability ( Po) without changing the unitary current. The D1 receptor blocker SCH-23390 blocked the dopamine effect, but the D2 receptor blocker sulpiride did not. The dopamine-mediated increase in ENaC activity was not a secondary effect of dopamine stimulation of Na-K-ATPase, since ouabain applied to the basolateral surface to block the activity of Na-K-ATPase did not alter dopamine-mediated ENaC activity. Protein kinase A (PKA) was not responsible for dopamine's effect since a PKA inhibitor, H89, did not reduce dopamine's effect. However, cpt-2-O-Me-cAMP, which selectively binds and activates EPAC (exchange protein activated by cAMP) but not PKA, increased ENaC Po. An Src inhibitor, PP2, and the phosphatidylinositol-3-kinase inhibitor, LY-294002, blocked dopamine's effect on ENaC. In addition, an MEK blocker, U0126, an inhibitor of phospholipase A2, and a protein phosphatase inhibitor also blocked the effect of dopamine on ENaC Po. Finally, since the cAMP-EPAC-Rap1 pathway also activates DARPP32 (32-kDa dopamine response protein phosphatase), we confirmed that dopamine phosphorylates DARPP32, and okadaic acid, which blocks phosphatases (DARPP32), also blocks dopamine's effect. In summary, dopamine increases ENaC activity by a cAMP-mediated alternative signaling pathway involving EPAC and Rap1, signaling molecules usually associated with growth-factor-activated receptors.
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DeFrance, J. F., R. W. Sikes, and R. B. Chronister. "Dopamine action in the nucleus accumbens." Journal of Neurophysiology 54, no. 6 (December 1, 1985): 1568–77. http://dx.doi.org/10.1152/jn.1985.54.6.1568.
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The action of dopamine was studied in the nucleus accumbens of acutely prepared rabbits. Dopamine was applied iontophoretically to those cells and cell populations that responded in a monosynaptic excitatory manner to ipsilateral fimbrial stimulation. This strategy was adopted to isolate the effects of dopamine on postsynaptic receptors thus avoiding the bias resulting from activation of presynaptic dopamine receptors on dopaminergic afferents. Dopamine was found to have a suppressive effect on the excitatory (N) component of the field response and on driven extracellular unitary discharges. The specificity of dopamine's effect with receptors was indicated by the facts that fluphenazine effectively antagonized dopamine's effect, whereas bicuculline did not. The effect of dopamine was dependent on the rate of fimbrial stimulation. Dopamine has a marked suppressive effect on the fimbria-induced response at 0.5 Hz of stimulation but not at 6.0 Hz. This frequency specificity could not be linked directly to a cyclic adenosine 3',5'-cyclic monophosphate (cyclic AMP) mechanism because the iontophoresis cyclic AMP and dibutyryl cyclic AMP had suppressive effects at both 0.5 and 6.0 Hz rates of stimulation. It is suggested that dopamine acts in the nucleus accumbens to increase the "signal-to-noise" ratio. This might be a form of "contrast enhancement" of an incoming hippocampal message.
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Shin, Seon H., Samia F. Hanna, Murray Hong, and Khem Jhamandas. "Reexamination of dopamine as the prolactin-release inhibiting factor (PIF): supplementary agent may be required for dopamine to function as the physiological PIF." Canadian Journal of Physiology and Pharmacology 68, no. 9 (September 1, 1990): 1226–30. http://dx.doi.org/10.1139/y90-184.
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A large number of studies have been performed concerning dopamine's inhibitory effect on prolactin release, but many of these studies have examined the effect of dopamine dissolved in a solution containing ascorbic acid. Ascorbic acid, routinely used to protect dopamine from oxidation, alone does not stimulate or inhibit prolactin release, but it can potentiate the inhibitory effect of dopamine in a static monolayer culture system by approximately 100 times. We have closely examined the inhibitory effect of dopamine on prolactin release in the absence of ascorbic acid using a perifusion system. Male rat adenohypophyses were dispersed with trypsin and cultured in a Petri dish to form cell clusters. Inhibition of prolactin release by dopamine (1 μmol/L) in the absence of ascorbic acid was sustained for only 63 min during the 2-h perifusion period. Following a 2-h period of incubation of dopamine in the same experimental solution, the dopamine concentration was reduced from 1 to 0.18 μmol/L, yet this "2-h-old dopamine" was still effective in inhibiting prolactin release (approximately 30 min). This result suggests that the lactotrophs may be desensitized by chronic exposure to a high concentration of dopamine in the absence of ascorbic acid. In contrast, when a low concentration of dopamine (3 nmol/L) containing ascorbic acid (0.1 mmol/L) was perifused, inhibition of prolactin release was sustained for the entire 2-h perifusion period. Although there may be a large number of explanations for dopamine's transient inhibitory effect on prolactin release, the present results suggest that dopamine may require supplementary agent(s) to effectively inhibit prolactin release and thus function as the prolactin release inhibitory factor (PIF). We propose ascorbic acid as a major candidate for the supplementary factor for the PIF.Key words: dopamine, somatostatin, prolactin, cell cluster, perifusion.
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Macedo-Lima, Matheus, and Luke Remage-Healey. "Dopamine Modulation of Motor and Sensory Cortical Plasticity among Vertebrates." Integrative and Comparative Biology 61, no. 1 (April 3, 2021): 316–36. http://dx.doi.org/10.1093/icb/icab019.
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Synopsis Goal-directed learning is a key contributor to evolutionary fitness in animals. The neural mechanisms that mediate learning often involve the neuromodulator dopamine. In higher order cortical regions, most of what is known about dopamine’s role is derived from brain regions involved in motivation and decision-making, while significantly less is known about dopamine’s potential role in motor and/or sensory brain regions to guide performance. Research on rodents and primates represents over 95% of publications in the field, while little beyond basic anatomy is known in other vertebrate groups. This significantly limits our general understanding of how dopamine signaling systems have evolved as organisms adapt to their environments. This review takes a pan-vertebrate view of the literature on the role of dopamine in motor/sensory cortical regions, highlighting, when available, research on non-mammalian vertebrates. We provide a broad perspective on dopamine function and emphasize that dopamine-induced plasticity mechanisms are widespread across all cortical systems and associated with motor and sensory adaptations. The available evidence illustrates that there is a strong anatomical basis—dopamine fibers and receptor distributions—to hypothesize that pallial dopamine effects are widespread among vertebrates. Continued research progress in non-mammalian species will be crucial to further our understanding of how the dopamine system evolved to shape the diverse array of brain structures and behaviors among the vertebrate lineage.
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Price, Christopher J., and Quentin J. Pittman. "Dopamine D4 Receptor Activation Inhibits Presynaptically Glutamatergic Neurotransmission in the Rat Supraoptic Nucleus." Journal of Neurophysiology 86, no. 3 (September 1, 2001): 1149–55. http://dx.doi.org/10.1152/jn.2001.86.3.1149.
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Oxytocin and vasopressin release from magnocellular neurons of the supraoptic nucleus is under the control of glutamate-dependent excitation. The supraoptic nucleus also receives a generalized dopaminergic input from hypothalamic sources. To determine if dopamine can influence this excitatory drive onto the magnocellular neurons, we used whole-cell patch clamp to record the effect of dopamine on evoked and miniature excitatory postsynaptic currents in rat hypothalamic slices. Dopamine exposure (30 μM to 1 mM) induced a large and reversible reduction in the amplitude of evoked excitatory postsynaptic current in nearly all magnocellular cells tested. D4 receptors appeared to mediate dopamine's activity, based on inhibition of the response with 50 μM clozapine, but not by SCH 23390 or sulpiride, and mimicry of dopamine's action with the D4 specific agonist, PD 168077. Analysis of paired-pulse experiments and miniature postsynaptic currents indicated that dopamine's action involved a presynaptic mechanism, since the frequency of miniature postsynaptic currents was reduced with dopamine exposure without any change in current kinetics or amplitude, while the paired-pulse ratio increased. We therefore have demonstrated for the first time a role for dopamine D4 receptors in the supraoptic nucleus in the presynaptic inhibition of glutamatergic neurotransmission onto magnocellular neurons.
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Shull, Timothy E., Jasmina Kurepa, and Jan A. Smalle. "Dopamine Inhibits Arabidopsis Growth through Increased Oxidative Stress and Auxin Activity." Stresses 3, no. 1 (March 2, 2023): 351–71. http://dx.doi.org/10.3390/stresses3010026.
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Like some bacterial species and all animals, plants synthesize dopamine and react to its exogenous applications. Despite dopamine’s widespread presence and activity in plants, its role in plant physiology is still poorly understood. Using targeted experimentation informed by the transcriptomic response to dopamine exposure, we identify three major effects of dopamine. First, we show that dopamine causes hypersensitivity to auxin indole-3-acetic acid by enhancing auxin activity. Second, we show that dopamine increases oxidative stress, which can be mitigated with glutathione. Third, we find that dopamine downregulates iron uptake mechanisms, leading to a decreased iron content—a response possibly aimed at reducing DA-induced oxidative stress. Finally, we show that dopamine-induced auxin sensitivity is downstream of glutathione biosynthesis, indicating that the auxin response is likely a consequence of DA-induced oxidative stress. Collectively, our results show that exogenous dopamine increases oxidative stress, which inhibits growth both directly and indirectly by promoting glutathione-biosynthesis-dependent auxin hypersensitivity.
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Pfeiffer-Linn, C., and E. M. Lasater. "Dopamine modulates in a differential fashion T- and L-type calcium currents in bass retinal horizontal cells." Journal of General Physiology 102, no. 2 (August 1, 1993): 277–94. http://dx.doi.org/10.1085/jgp.102.2.277.
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White bass (Roccus chrysops) retinal horizontal cells possess two types of voltage-activated calcium currents which have recently been characterized with regard to their voltage dependence and pharmacology (Sullivan, J., and E. M. Lasater. 1992. Journal of General Physiology. 99:85-107). A low voltage-activated transient current was identified which resembles the T-type calcium current described in a number of other preparations, along with a sustained high threshold, long-lasting calcium current that resembles the L-type calcium current. Here we report on the modulation of horizontal cell calcium channels by dopamine. Under whole-cell voltage clamp conditions favoring the expression of both calcium currents, dopamine had opposing actions on the two types of voltage-sensitive calcium currents in the same cone-type horizontal cell. The L-type calcium current was significantly potentiated by dopamine while the T-type current was simultaneously reduced. Dopamine had no effect on calcium currents in rod-type horizontal cells. Both of dopamine's actions were mimicked with the D1 receptor agonist, SKF 38393, and blocked by application of the D1 specific antagonist, SCH 23390. Dopamine's actions on the two types of calcium currents in white bass horizontal cells are mimicked by the cell membrane-permeant cyclic AMP derivative, 8-(4-chlorophenylthio)-cyclic AMP, suggesting that dopamine's action is linked to a cAMP-mediated second messenger system. Furthermore, the inhibitor of cAMP-dependent protein kinase blocked both of dopamine's actions on the voltage-dependent calcium channels when introduced through the patch pipette. This indicates that protein phosphorylation is involved in modulating horizontal cell calcium channels by dopamine. Taken together, these results show that dopamine has differential effects on the voltage-dependent calcium currents in retinal horizontal cells. The modulation of these currents may play a role in shaping the response properties of horizontal cells.
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Kundu, Aman, and Gyanesh Singh. "Dopamine synergizes with caffeine to increase the heart rate of Daphnia." F1000Research 7 (March 1, 2018): 254. http://dx.doi.org/10.12688/f1000research.12180.1.
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Dopamine is a key neurotransmitter, and is widely used as a central nervous system (CNS) agent. Dopamine plays an important role in humans, including a major role in reward and motivation behaviour. Several addictive drugs are well known to increase neuronal dopamine activity. We selected Daphnia, an important model organism, to investigate the effect(s) of selected CNS agents on heart rate. Dopamine’s effects on Daphnia’s heart has not been previously reported. Caffeine is a well-known and widely consumed stimulant. Ethanol is well known for its effects on both neurological and physiological processes in mammals. We tested the effect of dopamine on the heart rate of Daphnia, and compared its effect with caffeine and ethanol alone and in combination. Both caffeine and dopamine were found to instantly increase the heart rate of Daphnia in a dose-dependent manner. Interestingly, caffeine synergized with dopamine to increase Daphnia’s heart rate. As ethanol decreased the heart rate of Daphnia and dopamine increased the heart rate of Daphnia, we wanted to test the effect of these molecules in combination. Indeed, Dopamine was able to restore the ethanol-induced decrease in the heart rate of Daphnia. Effects of these CNS agents on Daphnia can possibly be correlated with similar effects in the case of mammals.
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Sarkar, D. K., K. Chaturvedi, S. Oomizu, N. I. Boyadjieva, and C. P. Chen. "Dopamine, Dopamine D2 Receptor Short Isoform, Transforming Growth Factor (TGF)-β1, and TGF-β Type II Receptor Interact to Inhibit the Growth of Pituitary Lactotropes." Endocrinology 146, no. 10 (October 1, 2005): 4179–88. http://dx.doi.org/10.1210/en.2005-0430.
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The neurotransmitter dopamine is known to inhibit prolactin secretion and the proliferation of lactotropes in the pituitary gland. In this study, we determined whether dopamine and TGFβ1 interact to regulate lactotropic cell proliferation. We found that dopamine and the dopamine agonist bromocriptine stimulated TGFβ1 secretion and TGFβ1 mRNA expression but inhibited lactotropic cell proliferation both in vivo and in vitro. The dopamine’s inhibitory action on lactotropic cell proliferation was blocked by a TGFβ1-neutralizing antibody. We also found that PR1 cells, which express low amounts of the dopamine D2 receptor, demonstrated reduced expression of TGFβ1 type II receptor and TGFβ1 mRNA levels and had undetectable levels of TGFβ1 protein. These cells showed a reduced TGFβ1 growth-inhibitory response. Constitutive expression of the D2 receptor short isoform, but not the D2 receptor long isoform, induced TGFβ1 and TGFβ1 type II receptor gene expression and recovered dopamine- and TGFβ1-induced growth inhibition in PR1 cells. The constitutive expression of D2 receptor short isoform also reduced the tumor cell growth rate. These data suggest that a TGFβ1 system may mediate, in part, the growth-inhibitory action of dopamine on lactotropes.
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Ryczko, Dimitri, Jackson J. Cone, Michael H. Alpert, Laurent Goetz, François Auclair, Catherine Dubé, Martin Parent, Mitchell F. Roitman, Simon Alford, and Réjean Dubuc. "A descending dopamine pathway conserved from basal vertebrates to mammals." Proceedings of the National Academy of Sciences 113, no. 17 (April 11, 2016): E2440—E2449. http://dx.doi.org/10.1073/pnas.1600684113.
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Dopamine neurons are classically known to modulate locomotion indirectly through ascending projections to the basal ganglia that project down to brainstem locomotor networks. Their loss in Parkinson’s disease is devastating. In lampreys, we recently showed that brainstem networks also receive direct descending dopaminergic inputs that potentiate locomotor output. Here, we provide evidence that this descending dopaminergic pathway is conserved to higher vertebrates, including mammals. In salamanders, dopamine neurons projecting to the striatum or brainstem locomotor networks were partly intermingled. Stimulation of the dopaminergic region evoked dopamine release in brainstem locomotor networks and concurrent reticulospinal activity. In rats, some dopamine neurons projecting to the striatum also innervated the pedunculopontine nucleus, a known locomotor center, and stimulation of the dopaminergic region evoked pedunculopontine dopamine release in vivo. Finally, we found dopaminergic fibers in the human pedunculopontine nucleus. The conservation of a descending dopaminergic pathway across vertebrates warrants re-evaluating dopamine’s role in locomotion.
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Foerde, Karin, Bernd Figner, Bradley B. Doll, Isabel C. Woyke, Erin Kendall Braun, Elke U. Weber, and Daphna Shohamy. "Dopamine Modulation of Intertemporal Decision-making: Evidence from Parkinson Disease." Journal of Cognitive Neuroscience 28, no. 5 (May 2016): 657–67. http://dx.doi.org/10.1162/jocn_a_00929.
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Choosing between smaller prompt rewards and larger later rewards is a common choice problem, and studies widely agree that frontostriatal circuits heavily innervated by dopamine are centrally involved. Understanding how dopamine modulates intertemporal choice has important implications for neurobiological models and for understanding the mechanisms underlying maladaptive decision-making. However, the specific role of dopamine in intertemporal decisions is not well understood. Dopamine may play a role in multiple aspects of intertemporal choices—the valuation of choice outcomes and sensitivity to reward delays. To assess the role of dopamine in intertemporal decisions, we tested Parkinson disease patients who suffer from dopamine depletion in the striatum, in either high (on medication, PDON) or low (off medication, PDOFF) dopaminergic states. Compared with both PDOFF and healthy controls, PDON made more farsighted choices and reduced their valuations less as a function of increasing time to reward. Furthermore, reduced discounting in the high dopaminergic state was robust across multiple measures, providing new evidence for dopamine's role in making decisions about the future.
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Bandyopadhyay, Susanta, and John J. Hablitz. "Dopaminergic Modulation of Local Network Activity in Rat Prefrontal Cortex." Journal of Neurophysiology 97, no. 6 (June 2007): 4120–28. http://dx.doi.org/10.1152/jn.00898.2006.
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Dopamine modulates prefrontal cortex excitability in complex ways. Dopamine's net effect on local neuronal networks is therefore difficult to predict based on studies on pharmacologically isolated excitatory or inhibitory connections. In the present work, we have studied the effects of dopamine on evoked activity in acute rat brain slices when both excitation and inhibition are intact. Whole cell recordings from layer II/III pyramidal cells under conditions of normal synaptic transmission showed that bath-applied dopamine (30 μM) increased the outward inhibitory component of composite postsynaptic currents, whereas inward excitatory currents were not significantly affected. Optical imaging with the voltage-sensitive dye N-(3-(triethylammonium)propyl)-4-(4-(p-diethylaminophenyl)buta-dienyl)pyridinium dibromide revealed that bath application of dopamine significantly decreased the amplitude, duration, and lateral spread of activity in local cortical networks. This effect of dopamine was observed both with single and train (5 at 20 Hz) stimuli. The effect was mimicked by the D1-like receptor agonist R(+)-6-chloro-7,8-dihydroxy-1-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (1 μM) and was blocked by R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (10 μM), a selective antagonist for D1-like receptors. The D2-like receptor agonist quinpirole (10 μM) had no significant effect on evoked dye signals. Our results suggest that dopamine's effect on inhibition dominates over that on excitation under conditions of normal synaptic transmission. Such neuromodulation by dopamine may be important for maintenance of stability in local neuronal networks in the prefrontal cortex.
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Davila, Nestor G., Laura J. Blakemore, and Paul Q. Trombley. "Dopamine Modulates Synaptic Transmission Between Rat Olfactory Bulb Neurons in Culture." Journal of Neurophysiology 90, no. 1 (July 2003): 395–404. http://dx.doi.org/10.1152/jn.01058.2002.
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The glomerular layer of the olfactory bulb (OB) contains synaptic connections between olfactory sensory neurons and OB neurons as well as connections among OB neurons. A subpopulation of external tufted cells and periglomerular cells (juxtaglomerular neurons) expresses dopamine, and recent reports suggest that dopamine can inhibit olfactory sensory neuron activation of OB neurons. In this study, whole cell electrophysiological and primary culture techniques were employed to characterize the neuromodulatory properties of dopamine on glutamatergic transmission between rat OB mitral/tufted (M/T) cells and interneurons. Immunocytochemical analysis confirmed the expression of tyrosine hydroxylase, the rate-limiting enzyme for dopamine synthesis, in a subpopulation of cultured neurons. D2 receptor immunoreactivity was also observed in cultured M/T cells. Dopamine reduced spontaneous excitatory synaptic events recorded in interneurons. Although the D1 receptor agonist SKF38393 and the D2 receptor agonist bromocriptine mesylate mimicked this effect, evoked excitatory postsynaptic potentials (EPSPs) recorded from monosynaptically coupled neuron pairs were attenuated by dopamine and bromocriptine but not by SKF38393 . Neither glutamate-evoked currents nor the membrane resistance of the postsynaptic interneuron were affected by dopamine. However, evoked calcium channel currents in the presynaptic M/T cell were diminished during the application of either dopamine or bromocriptine, but not SKF38393 . Dopamine suppressed calcium channel currents even after nifedipine blockade of L-type channels, suggesting that inhibition of the dihydropyridine-resistant high-voltage activated calcium channels implicated in transmitter release may mediate dopamine's effects on spontaneous and evoked synaptic transmission. Together, these data suggest that dopamine inhibits excitatory neurotransmission between M/T cells and interneurons via a presynaptic mechanism.
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Wood, A. N. "New roles for dopamine in motor skill acquisition: lessons from primates, rodents, and songbirds." Journal of Neurophysiology 125, no. 6 (June 1, 2021): 2361–74. http://dx.doi.org/10.1152/jn.00648.2020.
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Motor learning is a core aspect of human life and appears to be ubiquitous throughout the animal kingdom. Dopamine, a neuromodulator with a multifaceted role in synaptic plasticity, may be a key signaling molecule for motor skill learning. Though typically studied in the context of reward-based associative learning, dopamine appears to be necessary for some types of motor learning. Mesencephalic dopamine structures are highly conserved among vertebrates, as are some of their primary targets within the basal ganglia, a subcortical circuit important for motor learning and motor control. With a focus on the benefits of cross-species comparisons, this review examines how “model-free” and “model-based” computational frameworks for understanding dopamine’s role in associative learning may be applied to motor learning. The hypotheses that dopamine could drive motor learning either by functioning as a reward prediction error, through passive facilitating of normal basal ganglia activity, or through other mechanisms are examined in light of new studies using humans, rodents, and songbirds. Additionally, new paradigms that could enhance our understanding of dopamine’s role in motor learning by bridging the gap between the theoretical literature on motor learning in humans and other species are discussed.
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Liggins, John. "Roles of Dopamine D1 and D2 Receptors in Working Memory Function." McGill Science Undergraduate Research Journal 4, no. 1 (March 31, 2009): 39–45. http://dx.doi.org/10.26443/msurj.v4i1.77.
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Dopamine has been implicated in the modulation of working memory via its interactions with circuits located in the prefrontal cortex of rodents and non-human primates. However, the role that pathways triggered by dopamine receptor subtypes play in affecting processes of working memory remains unclear. In humans, the evidence for dopaminergic modulation of working memory is controversial and the neurological substrates for dopamine’s modulatory effects are not fully understood. This paper will review the major animal and human studies that implicate synaptic dopaminergic transmission in working memory function and will outline a new framework to clarify the specific contribution of dopamine D2 receptors to the performance of this cognitive function. Specifically, it is proposed that activation of hippocampal dopamine D2 receptors by chemical agonists could result in the enhancement of spatial working memory.
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Hsia, Albert Y., Jean-Didier Vincent, and Pierre-Marie Lledo. "Dopamine Depresses Synaptic Inputs Into the Olfactory Bulb." Journal of Neurophysiology 82, no. 2 (August 1, 1999): 1082–85. http://dx.doi.org/10.1152/jn.1999.82.2.1082.
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Both observations in humans with disorders of dopaminergic transmission and molecular studies point to an important role for dopamine in olfaction. In this study we found that dopamine receptor activation in the olfactory bulb causes a significant depression of synaptic transmission at the first relay between olfactory receptor neurons and mitral cells. This depression was found to be caused by activation of the D2 subtype of dopamine receptor and was reversible by a specific D2 receptor antagonist. A change in paired-pulse modulation during the depression suggests a presynaptic locus of action. The depression was found to occur independent of synaptic activity. These results provide the first evidence for dopaminergic control of inputs to the main olfactory bulb. The magnitude and locus of dopamine’s modulatory capabilities in the bulb suggest important roles for dopamine in odorant processing.
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Avram, Mihai, Felix Brandl, Franziska Knolle, Jorge Cabello, Claudia Leucht, Martin Scherr, Mona Mustafa, et al. "Aberrant striatal dopamine links topographically with cortico-thalamic dysconnectivity in schizophrenia." Brain 143, no. 11 (November 2020): 3495–505. http://dx.doi.org/10.1093/brain/awaa296.
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Abstract Aberrant dopamine function in the dorsal striatum and aberrant intrinsic functional connectivity (iFC) between distinct cortical networks and thalamic nuclei are among the most consistent large-scale brain imaging findings in schizophrenia. A pathophysiological link between these two alterations is suggested by theoretical models based on striatal dopamine’s topographic modulation of cortico-thalamic connectivity within cortico-basal-ganglia-thalamic circuits. We hypothesized that aberrant striatal dopamine links topographically with aberrant cortico-thalamic iFC, i.e. aberrant associative striatum dopamine is associated with aberrant iFC between the salience network and thalamus, and aberrant sensorimotor striatum dopamine with aberrant iFC between the auditory-sensorimotor network and thalamus. Nineteen patients with schizophrenia during remission of psychotic symptoms and 19 age- and sex-comparable control subjects underwent simultaneous fluorodihydroxyphenyl-l-alanine PET (18F-DOPA-PET) and resting state functional MRI (rs-fMRI). The influx constant kicer based on 18F-DOPA-PET was used to measure striatal dopamine synthesis capacity; correlation coefficients between rs-fMRI time series of cortical networks and thalamic regions of interest were used to measure iFC. In the salience network-centred system, patients had reduced associative striatum dopamine synthesis capacity, which correlated positively with decreased salience network-mediodorsal-thalamus iFC. This correlation was present in both patients and healthy controls. In the auditory-sensorimotor network-centred system, patients had reduced sensorimotor striatum dopamine synthesis capacity, which correlated positively with increased auditory-sensorimotor network-ventrolateral-thalamus iFC. This correlation was present in patients only. Results demonstrate that reduced striatal dopamine synthesis capacity links topographically with cortico-thalamic intrinsic dysconnectivity in schizophrenia. Data suggest that aberrant striatal dopamine and cortico-thalamic dysconnectivity are pathophysiologically related within dopamine-modulated cortico-basal ganglia-thalamic circuits in schizophrenia.
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SOYKA, MICHAEL. "DOPAMINE IS NOT DOPAMINE." Addiction 107, no. 2 (January 17, 2012): 248. http://dx.doi.org/10.1111/j.1360-0443.2011.03591.x.
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van den Pol, A. N., V. Cao, and A. B. Belousov. "Dopamine enhancement and depression of glutamate-regulated calcium and electrical activity in hypothalamic neurons." Journal of Neurophysiology 76, no. 6 (December 1, 1996): 3934–48. http://dx.doi.org/10.1152/jn.1996.76.6.3934.
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1. The neurotransmitter dopamine is found throughout the hypothalamus both in cell bodies and in axons originating from intra- and extrahypothalamic sources. To study the mechanisms of action of dopamine on cultured rat hypothalamic neurons, particularly in relation to Ca2+ regulation, we used Ca2+ digital imaging with fura-2 and whole cell patch-clamp recording. We focused on the modulatory actions of dopamine on glutamate. 2. Dopamine administration had little or no independent effect on intracellular Ca2+. However, in the presence of tetrodotoxin to block action potentials and action-potential-dependent transmitter release, dopamine (10 microM for 2-3 min) caused an increase in glutamate-evoked Ca2+ rises in 22% of 64 neurons and depressed glutamate-evoked Ca2+ rises in an equal number of neurons. Shorter exposure to dopamine reduced the number of responding cells. 3. Dopamine application to neurons with an elevated Ca2+ due to synaptic release of glutamate (in the absence of tetrodotoxin) generally caused a decrease in Ca2+ levels (40% of 106 neurons), but sometimes increased cytosolic Ca2+ (10% of 106 neurons). That dopamine influenced cells differently in conditions of spontaneous activity compared with evoked activity may be due to dopamine effects on presynaptic receptors detected under conditions of ongoing synaptic release of glutamate. 4. Dopamine modulation of glutamate responses was detected at early stages of neuronal development (embryonic day 18 after 2 days in vitro) and also after 60 days in vitro. 5. The D1, D2, and D3 dopamine receptor agonists SKF38393, quinpirole, and 7-OH-DPAT (+/- 7 hydroxy-dipropylaminotetralin) caused a reduction in Ca2+ levels raised by endogenous glutamate release or evoked by exogenous glutamate application. 6. To block the actions of dopamine released by hypothalamic neurons, D1 and D2 dopamine receptor antagonists were used. As with dopamine, dopamine antagonists had no effect on intracellular Ca2+ during glutamate receptor blockade. In the absence of glutamate receptor block, the D1 antagonist SCH23390 (1 microM) reduced Ca2+ in responding cells; in contrast, the D2 antagonist eticlopride (1 microM) generated a delayed increase in Ca2+ levels. 7. Dopamine is known to activate second messengers through G proteins independent of changes in membrane potential or input resistance. Whole cell recording was used to demonstrate that, parallel to the modulation of Ca2+, dopamine exerted a dramatic change in glutamate-mediated electrical activity, generally depressing activity and hyperpolarizing the membrane potential (8 of 15 neurons). In a smaller number of neurons (5 of 15), dopamine enhanced glutamate-mediated excitatory activity. 8. Dopamine-evoked changes in membrane potential were in part mediated through modulation of glutamate actions. Dopamine depressed glutamate-evoked currents in a dose-dependent fashion, with Hill slopes in individual neurons ranging from 0.3 to 0.6. Dopamine could also evoke a direct hyperpolarizing action on hypothalamic neurons in the presence of tetrodotoxin or glutamate receptor blockers, at least in part by opening K+ channels. 9. Glutamate plays an important role as a primary excitatory transmitter within the hypothalamus. Our data support the hypothesis that a major mechanism of dopamine's influence on hypothalamic neurons involves the modulation of glutamate's excitatory action, mostly by inhibition. This is consistent with the hypothesis that modulation of glutamate activity may be an important mechanism of dopamine action throughout the nervous system.
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Awenowicz, Patrick W., and Linda L. Porter. "Local Application of Dopamine Inhibits Pyramidal Tract Neuron Activity in the Rodent Motor Cortex." Journal of Neurophysiology 88, no. 6 (December 1, 2002): 3439–51. http://dx.doi.org/10.1152/jn.00078.2002.
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Cortical neurons respond in a variety of ways to locally applied dopamine, perhaps because of the activation of different receptors within or among subpopulations of cells. This study was conducted to assess the effects of dopamine and the receptor subtypes that mediate the responses of a specific population of neurons, the pyramidal tract neurons (PTNs) in the rodent motor cortex. The specific subfamilies of dopamine receptors expressed by PTNs also were determined. PTNs were identified by antidromic stimulation in intact animals. Extracellular recordings of their spontaneous activity and glutamate-induced excitation were performed with multi-barrel pipettes to allow simultaneous recording and iontophoresis of several drugs. Prolonged (30 s) application of dopamine caused a progressive, nonlinear decrease in spontaneous firing rates for nearly all PTNs, with significant reductions from baseline spontaneous activity (71% of baseline levels) occurring between 20 and 30 s of iontophoresis. The D1 selective (SCH23390) and the D2 selective (eticlopride) antagonists were both effective in blocking dopamine-induced inhibition in nearly all PTNs. Mean firing levels were maintained within 3% of baseline levels during co-application of the D1 antagonist with dopamine and within 11% of baseline levels during co-application of the D2 antagonist and dopamine. SCH23390 was ineffective however, in 2 of 16 PTNs, and eticlopride was ineffective in 3 PTNs. The dopamine blockade by both antagonists in most neurons, along with the selective blockade by one, but not the other antagonist in a few neurons indicate that the overall population of PTNs exhibits a heterogeneous expression of dopamine receptors. The firing rate of PTNs was significantly enhanced by iontophoresis of glutamate (mean = 141% of baseline levels). These increases were attenuated significantly (mean= 98% of baseline) by co-application with dopamine in all PTNs, indicating dopaminergic interactions with glutamate transmission. The expression of dopamine receptors was studied with dual-labeling techniques. PTNs were identified by retrograde labeling with fast blue and the D1a, D2, or D5 receptor proteins were stained immunohistochemically. Some, but not all PTNs, showed labeling for D1a, D2, or D5 receptors. The D1a and D2 receptor immunoreactivity was observed primarily in the somata of PTNs, whereas D5 immunoreactivity extended well into the apical dendrites of PTNs. In accordance with findings of D1 and D2 receptor antagonism of dopamine's actions, the identification of three DA receptor subtypes on PTNs suggests that dopamine can directly modulate PTN activity through one or more receptor subtypes.
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Chassignolle, Morgane, Ljubica Jovanovic, Catherine Schmidt-Mutter, Guillaume Behr, Anne Giersch, and Jennifer T. Coull. "Dopamine Precursor Depletion in Healthy Volunteers Impairs Processing of Duration but Not Temporal Order." Journal of Cognitive Neuroscience 33, no. 5 (April 1, 2021): 946–63. http://dx.doi.org/10.1162/jocn_a_01700.
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Abstract Studies in animals and humans have implicated the neurotransmitter dopamine in duration processing. However, very few studies have examined dopamine's involvement in other forms of temporal processing such as temporal order judgments. In a randomized within-subject placebo-controlled design, we used acute phenylalanine/tyrosine depletion (APTD) to reduce availability of the dopamine precursors tyrosine and phenylalanine in healthy human volunteers. As compared to a nutritionally balanced drink, APTD significantly impaired the ability to accurately reproduce interval duration in a temporal reproduction task. In addition, and confirming previous findings, the direction of error differed as a function of individual differences in underlying dopamine function. Specifically, APTD caused participants with low baseline dopamine precursor availability to overestimate the elapse of time, whereas those with high dopamine availability underestimated time. In contrast to these effects on duration processing, there were no significant effects of APTD on the accuracy of discriminating the temporal order of visual stimuli. This pattern of results does not simply represent an effect of APTD on motor, rather than perceptual, measures of timing because APTD had no effect on participants' ability to use temporal cues to speed RT. Our results demonstrate, for the first time in healthy volunteers, a dopaminergic dissociation in judging metrical (duration) versus ordinal (temporal order) aspects of time.
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DÖNMEZ, Ayşegül, and Gülseren KESKİN. "COVID-19 Pandemisinde Psikotik Süreç: Dopamin Etkisi." Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 16, no. 2 (November 26, 2023): 203–9. http://dx.doi.org/10.18863/pgy.1181901.
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The global impact of severe acute respiratory syndrome COVID-19 has extended beyond physical health, significantly affecting mental well-being worldwide. Amid the pandemic's initial wave, COVID-19 patients exhibited symptoms of post-traumatic stress disorder and notably depressive symptoms. Alongside manifestations like delirium, confusion, agitation, and altered consciousness, prevalent mental health issues during the pandemic encompassed depression, anxiety, and insomnia. Individuals recovering from COVID-19 may face enduring psychiatric challenges post-hospital discharge, potentially linked to dopamine. Dopaminergic receptors might heighten the susceptibility of certain viruses to bind with the central nervous system, instigating viral encephalitis in the virus's early infection stages. Dopamine could also disrupt the human basal carotid body's respiratory response to hypoxia. Additionally, the virus could manipulate the immune system by elevating dopamine levels, facilitating viral entry. These findings emphasize the significance of considering dopamine's role in the diagnosis, treatment, and care of COVID-19 patients and those with diagnosed psychosis. Tailored interventions are crucial for individuals exhibiting distinctive features. Another intriguing aspect worthy of investigation is whether dopamine confers protection against COVID-19. This review article aims to elucidate the intricate relationship between the impactful COVID-19 pandemic and dopamine, shedding light on its potential implications and avenues for further exploration.
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Nour, Matthew M., Tarik Dahoun, Philipp Schwartenbeck, Rick A. Adams, Thomas H. B. FitzGerald, Christopher Coello, Matthew B. Wall, Raymond J. Dolan, and Oliver D. Howes. "Dopaminergic basis for signaling belief updates, but not surprise, and the link to paranoia." Proceedings of the National Academy of Sciences 115, no. 43 (October 8, 2018): E10167—E10176. http://dx.doi.org/10.1073/pnas.1809298115.
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Distinguishing between meaningful and meaningless sensory information is fundamental to forming accurate representations of the world. Dopamine is thought to play a central role in processing the meaningful information content of observations, which motivates an agent to update their beliefs about the environment. However, direct evidence for dopamine’s role in human belief updating is lacking. We addressed this question in healthy volunteers who performed a model-based fMRI task designed to separate the neural processing of meaningful and meaningless sensory information. We modeled participant behavior using a normative Bayesian observer model and used the magnitude of the model-derived belief update following an observation to quantify its meaningful information content. We also acquired PET imaging measures of dopamine function in the same subjects. We show that the magnitude of belief updates about task structure (meaningful information), but not pure sensory surprise (meaningless information), are encoded in midbrain and ventral striatum activity. Using PET we show that the neural encoding of meaningful information is negatively related to dopamine-2/3 receptor availability in the midbrain and dexamphetamine-induced dopamine release capacity in the striatum. Trial-by-trial analysis of task performance indicated that subclinical paranoid ideation is negatively related to behavioral sensitivity to observations carrying meaningful information about the task structure. The findings provide direct evidence implicating dopamine in model-based belief updating in humans and have implications for understating the pathophysiology of psychotic disorders where dopamine function is disrupted.
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Gleason, Christine A., Roderick Robinson, Andrew P. Harris, Dennis E. Mayock, and Richard J. Traystman. "Cerebrovascular effects of intravenous dopamine infusions in fetal sheep." Journal of Applied Physiology 92, no. 2 (February 1, 2002): 717–24. http://dx.doi.org/10.1152/japplphysiol.00600.2001.
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Preterm infants are often treated with intravenous dopamine to increase mean arterial blood pressure (MAP). However, there are few data regarding cerebrovascular responses of developing animals to dopamine infusions. We studied eight near-term and eight preterm chronically catheterized unanesthetized fetal sheep. We measured cerebral blood flow and calculated cerebral vascular resistance (CVR) at baseline and during dopamine infusion at 2.5, 7.5, 25, and 75 μg · kg−1 · min−1. In preterm fetuses, MAP increased only at 75 μg · kg−1 · min−1 (25 ± 5%), whereas in near-term fetuses MAP increased at 25 μg · kg−1 · min−1 (28 ± 4%) and further at 75 μg · kg−1 · min−1 (51 ± 3%). Dopamine infusion was associated with cerebral vasoconstriction in both groups. At 25 μg · kg−1 · min−1, CVR increased 77 ± 51% in preterm fetuses and 41 ± 11% in near-term fetuses, and at 75 μg · kg−1 · min−1, CVR increased 80 ± 33% in preterm fetuses and 83 ± 21% in near-term fetuses. We tested these responses to dopamine in 11 additional near-term fetuses under α-adrenergic blockade (phenoxybenzamine, n = 5) and under dopaminergic D1-receptor blockade (SCH-23390, n = 6). Phenoxybenzamine completely blocked dopamine's pressor and cerebral vasoconstrictive effects, while D1-receptor blockade had no effect. Therefore, in unanesthetized developing fetuses, dopamine infusion is associated with cerebral vasoconstriction, which is likely an autoregulatory, α-adrenergic response to an increase in blood pressure.
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AVŞAR, Orçun. "Role of Dopamine and Dopamine Receptors in Tumor Progression and Therapy." Journal of Literature Pharmacy Sciences 9, no. 3 (2020): 250–58. http://dx.doi.org/10.5336/pharmsci.2020-73635.
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McConkey, G., J. Webster, E. Prandovszky, and M. Kaushik. "Neurological sequalae and toxoplasma infection: Possible mechanisms to explain associations with schizophrenia." European Psychiatry 26, S2 (March 2011): 2123. http://dx.doi.org/10.1016/s0924-9338(11)73826-3.
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Latent infection with the common intracellular protozoan parasite Toxoplasma gondii has been shown to result in altered behaviour of its host. This behaviour manipulation has been proposed to increase predation of the intermediate host (e.g. rodents and birds) enhancing parasite transmission. Other psychologicalsequalae have also been associated with latent toxoplasmosis including human affective disorders, as human are accidental hosts for Toxoplasma. During cyst stages of the life cycle found in the brain and other tissues, there is a complex interaction between the parasite and the host. Our research is concerned with the possibility that the parasite-induced behavioural changes are mediated by neurotransmitters. Potential factors in neurotransmitter levels include the location of the cyst, the host immune response, and direct parasite products. The cyst is found in many brain regions but elevated numbers have been reported in the hippocampus, amygdala, and nucleus accumbens. The host response involves interferon gamma suppressing growth through tryptophan degradation that could decrease serotonin levels. The parasite could directly manipulate the host brain through altering dopamine levels. We have found a change in dopamine associated with infection. Indeed, the parasite itself encodes the rate-limiting enzyme in dopamine synthesis, tyrosine hydroxylase. Dopamine's role is also supported by finding haloperidol, a dopamine antagonist, blocks manipulation of rodents by Toxoplasma. Our current investigations of alterations in neurotransmitter levels during chronic infection and association with brain cysts will be presented. Our data presents an interesting interplay with the ‘dopamine hypothesis’ that has postulated a link between elevated dopamine and schizophrenia.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 706 (June 1998): 7. http://dx.doi.org/10.2165/00128415-199807060-00019.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 745 (April 1999): 8. http://dx.doi.org/10.2165/00128415-199907450-00029.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 642 (March 1997): 8. http://dx.doi.org/10.2165/00128415-199706420-00024.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1203 (May 2008): 18–19. http://dx.doi.org/10.2165/00128415-200812030-00056.
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Costa, Kauê Machado, and Geoffrey Schoenbaum. "Dopamine." Current Biology 32, no. 15 (August 2022): R817—R824. http://dx.doi.org/10.1016/j.cub.2022.06.060.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1266 (August 2009): 17. http://dx.doi.org/10.2165/00128415-200912660-00052.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1244 (March 2009): 15. http://dx.doi.org/10.2165/00128415-200912440-00043.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 353 (June 1991): 5. http://dx.doi.org/10.2165/00128415-199103530-00023.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1309 (July 2010): 19. http://dx.doi.org/10.2165/00128415-201013090-00057.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1040 (February 2005): 10. http://dx.doi.org/10.2165/00128415-200510400-00031.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1046 (April 2005): 12. http://dx.doi.org/10.2165/00128415-200510460-00041.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 1052 (May 2005): 9. http://dx.doi.org/10.2165/00128415-200510520-00029.
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&NA;. "Dopamine." Reactions Weekly &NA;, no. 517 (September 1994): 7. http://dx.doi.org/10.2165/00128415-199405170-00028.
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Velasco, Manuel, and Augusta Luchsinger. "Dopamine." American Journal of Therapeutics 5, no. 1 (January 1998): 37–44. http://dx.doi.org/10.1097/00045391-199801000-00007.
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Nieoullon, André, and Antoine Coquerel. "Dopamine." Current Opinion in Neurology 16 (December 2003): S3—S9. http://dx.doi.org/10.1097/00019052-200312002-00002.
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Peng, Shichun, Doris J. Doudet, Vijay Dhawan, and Yilong Ma. "Dopamine." PET Clinics 8, no. 4 (October 2013): 469–85. http://dx.doi.org/10.1016/j.cpet.2013.08.003.
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Bandyopadhyay, Susanta, Carlos Gonzalez-Islas, and John J. Hablitz. "Dopamine Enhances Spatiotemporal Spread of Activity in Rat Prefrontal Cortex." Journal of Neurophysiology 93, no. 2 (February 2005): 864–72. http://dx.doi.org/10.1152/jn.00922.2004.
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Dopaminergic modulation of prefrontal cortex (PFC) is important for neuronal integration in this brain region known to be involved in cognition and working memory. Because of the complexity and heterogeneity of the effect of dopamine on synaptic transmission across layers of the neocortex, dopamine's net effect on local circuits in PFC is difficult to predict. We have combined whole cell patch-clamp recording and voltage-sensitive dye imaging to examine the effect of dopamine on the excitability of local excitatory circuits in rat PFC in vitro. Whole cell voltage-clamp recording from visually identified layer II/III pyramidal neurons in rat brain slices revealed that, in the presence of bicuculline (10 μM), bath-applied dopamine (30–60 μM) increased the amplitude of excitatory postsynaptic currents (EPSCs) evoked by weak intracortical stimulus. The effect was mimicked by the selective D1 receptor agonist SKF 81297 (1 μM). Increasing stimulation resulted in epileptiform discharges. SKF 81297 (1 μM) significantly lowered the threshold stimulus required for generating epileptiform discharges to 83% of control. In the imaging experiments, bath application of dopamine or SKF 81297 enhanced the spatiotemporal spread of activity in response to weak stimulation and previously subthreshold stimulation resulted in epileptiform activity that spread across the whole cortex. These effects could be blocked by the selective D1 receptor antagonist SCH 23390 (10 μM) but not by the D2 receptor antagonist eticlopride (5 μM). These results indicate that dopamine, by a D1 receptor–mediated mechanism, enhances spatiotemporal spread of synaptic activity and lowers the threshold for epileptiform activity in local excitatory circuits within PFC.
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Harris-Warrick, R. M., L. M. Coniglio, R. M. Levini, S. Gueron, and J. Guckenheimer. "Dopamine modulation of two subthreshold currents produces phase shifts in activity of an identified motoneuron." Journal of Neurophysiology 74, no. 4 (October 1, 1995): 1404–20. http://dx.doi.org/10.1152/jn.1995.74.4.1404.
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1. The lateral pyloric (LP) neuron is a component of the 14-neuron pyloric central pattern generator in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus. In the pyloric rhythm, this neuron fires rhythmic bursts of action potentials whose phasing depends on the pattern of synaptic inhibition from other network neurons and on the intrinsic postinhibitory rebound properties of the LP cell itself. Bath-applied dopamine excites the LP cell and causes its activity to be phase advanced in the pyloric motor pattern. At least part of this modulatory effect is due to dopaminergic modulation of the intrinsic rate of postinhibitory rebound in the LP cell. 2. The LP neuron was isolated from all detectable synaptic input. We measured the rate of recovery after 1-s hyperpolarizing current injections of varying amplitudes, quantifying the latency to the first spike following the hyperpolarizing prepulse and the interval between the first and second action potentials. Dopamine reduced both the first spike latency and the first interspike interval (ISI) in the isolated LP neuron. During the hyperpolarizating pre-steps, the LP cell showed a slow depolarizing sag voltage that was enhanced by dopamine. 3. We used voltage clamp to analyze dopamine modulation of subthreshold ionic currents whose activity is affected by hyperpolarizing prepulses. Dopamine modulated the transient potassium current IA by reducing its maximal conductance and shifting its voltage dependence for activation and inactivation to more depolarized voltages. This outward current is normally transiently activated after hyperpolarization of the LP cell, and delays the rate of postinhibitory rebound; by reducing IA, dopamine thus accelerates the rate of rebound of the LP neuron. 4. Dopamine also modulated the hyperpolarization-activated inward current Ih by shifting its voltage dependence for activation 20 mV in the depolarizing direction and accelerating its rate of activation. This enhanced inward current helps accelerate the rate of rebound in the LP cell after inhibition. 5. The relative roles of Ih and IA in determining the first spike latency and first ISI were explored using pharmacological blockers of Ih (Cs+) and IA [4-aminopyridine (4-AP)]. Blockade of Ih prolonged the first spike latency and first ISI, but only slightly reduced the net effect of dopamine. In the continued presence of Cs+, blockade of IA with 4-AP greatly shortened the first spike latency and first ISI. Under conditions where both Ih and IA were blocked, dopamine had no additional effect on the LP cell. 6. We used the dynamic clamp technique to further study the relative roles of IA and Ih modulation in dopamine's phase advance of the LP cell. We blocked the endogenous Ih with Cs+ and replaced it with a simulated current generated by a computer model of Ih. The neuron with simulated Ih gave curves relating the hyperpolarizing prepulse amplitude to first spike latency that were the same as in the untreated cell. Changing the computer parameters of the simulated Ih to those induced by dopamine without changing IA caused only a slight reduction in first spike latency, which was approximately 20% of the total reduction caused by dopamine in an untreated cell. Bath application of dopamine in the presence of Cs+ and simulated Ih (with control parameters) allowed us to determine the effect of altering IA but not Ih: this caused a significant reduction in first spike latency, but it was still only approximately 70% of the effect of dopamine in the untreated cell. Finally, in the continued presence of dopamine, changing the parameters of the simulated Ih to those observed with dopamine reduced the first spike latency to that seen with dopamine in the untreated cell. 7. We generated a mathematical model of the lobster LP neuron, based on the model of Buchholtz et al. for the crab LP neuron.
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Myslivecek, Jaromir. "Dopamine and Dopamine-Related Ligands Can Bind Not Only to Dopamine Receptors." Life 12, no. 5 (April 19, 2022): 606. http://dx.doi.org/10.3390/life12050606.
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The dopaminergic system is one of the most important neurotransmitter systems in the central nervous system (CNS). It acts mainly by activation of the D1-like receptor family at the target cell. Additionally, fine-tuning of the signal is achieved via pre-synaptic modulation by the D2-like receptor family. Some dopamine drugs (both agonists and antagonists) bind in addition to DRs also to α2-ARs and 5-HT receptors. Unfortunately, these compounds are often considered subtype(s) specific. Thus, it is important to consider the presence of these receptor subtypes in specific CNS areas as the function virtually elicited by one receptor type could be an effect of other—or the co-effect of multiple receptors. However, there are enough molecules with adequate specificity. In this review, we want to give an overview of the most common off-targets for established dopamine receptor ligands. To give an overall picture, we included a discussion on subtype selectivity. Molecules used as antipsychotic drugs are reviewed too. Therefore, we will summarize reported affinities and give an outline of molecules sufficiently specific for one or more subtypes (i.e., for subfamily), the presence of DR, α2-ARs, and 5-HT receptors in CNS areas, which could help avoid ambiguous results.
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Liu, Yuan, Hao Zhan, Sarah Skelton, and Bruce P. Lee. "Marine Adhesive Containing Nanocomposite Hydrogel with Enhanced Materials and Bioadhesive Properties." MRS Proceedings 1569 (2013): 33–38. http://dx.doi.org/10.1557/opl.2013.765.
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ABSTRACT4-arm poly(ethylene glycol) end-capped with mimics of adhesive moiety found in mussel adhesive protein, dopamine, was combined with a biocompatible nano-silicate, Laponite, in creating a nanocomposite hydrogel with improved materials and adhesive properties. Dopamine’s ability to form both irreversible covalent (cohesive and interfacial) and reversible physical (with Laponite) crosslinks was exploited in creating an injectable tissue adhesive. Incorporation of Laponite did not interfere with the curing of the adhesive. In some instances, increasing Laponite content reduced gelation time as dopamine-Laponite bond reduced the required number of covalent bonds needed for network formation. Incorporation of Laponite also increased compressive materials properties (e.g., max strength, energy to failure, etc.) of the nanocomposite without compromising its compliance as strain at failure was also increased. From lap shear adhesion test using wetted pericardium as the substrate, incorporating Laponite increased work of adhesion by 5 fold over that of control. Strong, physical bonds formed between dopamine and Laponite increased bulk materials properties, which contributed to the enhanced adhesive properties.
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Buu, N. T., J. Duhaime, and O. Kuchel. "Handling of dopamine and dopamine sulfate by isolated perfused rat kidney." American Journal of Physiology-Renal Physiology 250, no. 6 (June 1, 1986): F975—F979. http://dx.doi.org/10.1152/ajprenal.1986.250.6.f975.
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The possible contribution of circulating dopamine sulfate to urinary free dopamine and the synthesis of norepinephrine by the renal nerves were examined in the isolated perfused rat kidney. Perfusion of the kidney with dopamine sulfate did not yield significant amounts of free dopamine indicating that, unlike L-dopa, dopamine sulfate is not a good source of urinary free dopamine. The excretion of dopamine sulfate was slower than or comparable with that of free dopamine, suggesting that sulfoconjugation is not a mechanism to facilitate the excretion of free dopamine. Unlike free dopamine, dopamine sulfate was not metabolized by renal catechol-O-methyltransferase or monoamine oxidase. Perfusion of L-dopa and free dopamine led to the generation of norepinephrine in the kidney. This synthesis was abolished when the kidney was denervated, suggesting that the renal nerves were the main sites of the norepinephrine synthesis. Both norepinephrine and dopamine were rapidly metabolized by catechol-O-methyltransferase and monoamine oxidase, but renal phenolsulfotransferase appeared to have no action on the catecholamines.
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AYHAN, Murat, and Ali BAYRİ. "SUYUN ŞİZOFRENİYE ETKİLERİNİN İKİ FARKLI NÖROTRANSMİTTER BAĞLAMINDA TEORİK OLARAK İNCELENMESİ." Sağlık Bilimleri Dergisi, February 22, 2022. http://dx.doi.org/10.34108/eujhs.885229.
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Suyun hayatımızdaki yeri ve sağlıklı bir yaşam sürmemiz için suyun ne kadar önemli olduğu herkes tarafından kabul gören bir gerçektir. Su günlük hayatta içecek olarak kullanılmasının yanında ayrıca çeşitli yöntemler aracılığıyla tedavi unsuru olarak ta tercih edilmektedir. Çalışmamızda şizofreni hastalarına etkiyen iki nörotransmitter, dopamin(C8H11NO2) ve seratonin(C10H12N2O) üzerinde duruldu. Bu iki nörotarsmiterin üç boyutlu çizimleri gaussian programı aracılığıyla yapıldı. Bu iki nörotrasmitterin moleküller yapısının yeterli miktarda su ile etkileşmesiyle meydana gelen değişikliklere bakıldı. Moleküller yapıların su ile etkileşmesi ile bağ açılarında ve bağ uzunluklarındaki değişimler irdelenerek sinapsların elektrostatik ileti mekanizması ele alındı. Nörotransmitter iki yapının geometrik optizimazyonu Gaussian 09W programında HF(Hatree- Fock) hesaplama yöntemindeki TD-SCF metod ve LanL2DZ baz seti kullanılarak yapıldı. Geometrik optimizasyon sonucu oluşan moleküllerin en yüksek dolu moleküler orbital (HOMO) ve en düşük boş moleküler orbital (LUMO) değerlerinin hesaplamaları yapıldı. İki yapınında su bağlanmadan önceki veriler ile bağlandıktan sonra elde edilen karşılaştırıldı. nörotransmitterlerin bulunduğu ortamda su kaynaklı meydana gelen değişimler irdelendi. Su ile etkileşim sonucu seratoninde bulunan atomların arasındaki bağ uzunlukları genellikle artış gösterirken, atomlar arasındaki bağ açıları ise genellikle azalış göstermektedir. Buna karşın dopaminde tam tersi bir durum gözlenmektedir. Su ile dopaminin etkileşmesi sonucu dopamindeki atomların bağ uzunlukları genellikle azalış gösterirken, atomlar arasındaki bağ açıları artış göstermektedir. Dopamin ve seratonin nörotransmitterleri elektrostatik olarak birbirlerine göre tersinir çalışmaktadır. Bu ise iki nörotransmitterin beyin kimyasının işleyişine etkilerinin farklı olduğunu söyleyebiliriz. Yeterli miktarda suyun dopamine ait reaksiyonları kolaylaştırıcı etkisi 0.401eV civarında iken suyun seratonine ait reaksiyonları kolaylaştırıcı etkisi 3.214eV civarında idi. Buradan da görüldüğü üzere yeterli miktarda su ile etkileşime giren seratonin, dopaminden yaklaşık olarak sekiz kat daha fazla etkinliğini arttırdığını bize söylemektedir
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Sudarma, Nyoman, Mrs Irdhawati, and James Sibarani. "KINETIKA TRANSFER ION DOPAMIN PADA ANTARMUKA AIR-NITROBENZENA SECARA VOLTAMETRI." Seminar Ilmiah Nasional Teknologi, Sains, dan Sosial Humaniora (SINTESA) 1 (December 19, 2018). http://dx.doi.org/10.36002/snts.v0i0.518.
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ABSTRAKPenelitian transfer ion dopamin secara elektrokimia pada antarmuka air-nitrobenzena dengan metode voltametri telah dilakukan. Pengukuran transfer ion ini menggunakan sistem 3 elektroda yaitu 2 elektroda Ag/AgCl sebagai elektroda kerja dan elektroda pembanding, dan elekroda platina sebagai elektroda pembantu.Penelitian diawali dengan pembuatan elektroda pembanding Ag/AgCl yang kemudian dilakukan karakterisasi terhadap elektroda tersebut. Kinetika transfer ion dopamin diketahui dengan melakukan perhitungan nilai potensial standar dan energi bebas Gibbs transfer ion dopamin melalui pengukuran larutan standar dopamin dan tetra metil amonium klorida (TMACl) dengan metode voltametri siklik. Hasil karakterisasi elektroda pembanding Ag/AgCl menunjukkan kelayakan elekroda dengan nilai slope sebesar 60,71 dan r = 0,9984. Potensial standar transfer ion dopamine adalah 0,173 V dan proses berlangsung secara spontan dengan perubahan energi bebas Gibbs (ΔG) sebesar -16,64 kJ/mol.Kata kunci: transfer ion dopamin, antarmuka air-nitrobenzena, voltametriABSTRACTResearch dopamine electrochemical ion transfer at the water-nitrobenzena interface by voltammetry method has been conducted. This measurement uses three electrode system that was two electrode Ag/AgCl electrode as the working electrode and reference electrode, and platinum electrodes as counter electrode. The research comparison begins with the manufacture of electrodes Ag/AgCl were then performed to characterize the electrode. Kinetics of transfer ion dopamine is known to perform calculations potential sandard value and Gibbs energy through measurements the dopamine standard and ammonium chloride and metal tetra (TMACl) solution by cyclic voltammetry method. The results of the reference electrode characterization of Ag/ AgCl electrodes demonstrate the feasibility of the slope value of 60.71 and r = 0.9984. Dopamine standard ion transfer potential is 0.173 V and the process takes place spontaneously with the change in Gibbs free energy (ΔG) of -16.64 kJ/ mol.Keywords: dopamine transfer ion, water-nitrobenzene interface, voltammetry.
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Wang, Alyssa. "An Investigation of Dopamine’s Role in Six Psychiatric Illnesses." Journal of Student Research 10, no. 1 (March 31, 2021). http://dx.doi.org/10.47611/jsrhs.v10i1.1394.
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This paper aims to investigate the neurotransmitter dopamine’s role in six prevalent psychiatric disorders: attention-deficit disorder, autism spectrum disorder, bipolar disorder, major depression, post-traumatic stress disorder, and schizophrenia. Although dopamine’s contribution to schizophrenia is the most understood, dopamine’s role in other disorders is also an increasing area of research. Dopamine affects reward-motivated behavior, motor control, cognition, and possesses many other sub-functions as well. Dysfunction in dopamine firing rate, firing time, tonic and phasic levels, and receptor and transporter density can lead to numerous diseases and symptoms. Having a better understanding of how dopamine affects these illnesses specifically can lead to the development of more effective treatment and medication. Thus, the analysis of the studies and proposals for how dopamine is involved in various mental disorders are discussed in this review.