Journal articles: 'Kv3'

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Bocksteins, Elke, Gerda Van de Vijver, Pierre-Paul Van Bogaert, and Dirk J. Snyders. "Kv3 channels contribute to the delayed rectifier current in small cultured mouse dorsal root ganglion neurons." American Journal of Physiology-Cell Physiology 303, no. 4 (August 15, 2012): C406—C415. http://dx.doi.org/10.1152/ajpcell.00343.2011.

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Delayed rectifier voltage-gated K+ (KV) channels are important determinants of neuronal excitability. However, the large number of KV subunits poses a major challenge to establish the molecular composition of the native neuronal K+ currents. A large part (∼60%) of the delayed rectifier current ( IK) in small mouse dorsal root ganglion (DRG) neurons has been shown to be carried by both homotetrameric KV2.1 and heterotetrameric channels of KV2 subunits with silent KV subunits (KVS), while a contribution of KV1 channels has also been demonstrated. Because KV3 subunits also generate delayed rectifier currents, we investigated the contribution of KV3 subunits to IK in small mouse DRG neurons. After stromatoxin (ScTx) pretreatment to block the KV2-containing component, application of 1 mM TEA caused significant additional block, indicating that the ScTx-insensitive part of IK could include KV1, KV3, and/or M-current channels (KCNQ2/3). Combining ScTx and dendrotoxin confirmed a relevant contribution of KV2 and KV2/KVS, and KV1 subunits to IK in small mouse DRG neurons. After application of these toxins, a significant TEA-sensitive current (∼19% of total IK) remained with biophysical properties that corresponded to those of KV3 currents obtained in expression systems. Using RT-PCR, we detected KV3.1–3 mRNA in DRG neurons. Furthermore, Western blot and immunocytochemistry using KV3.1-specific antibodies confirmed the presence of KV3.1 in cultured DRG neurons. These biophysical, pharmacological, and molecular results demonstrate a relevant contribution (∼19%) of KV3-containing channels to IK in small mouse DRG neurons, supporting a substantial role for KV3 subunits in these neurons.

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ZHU, Jing, Barbara GOMEZ, Itaru WATANABE, and William B. THORNHILL. "Amino acids in the pore region of Kv1 potassium channels dictate cell-surface protein levels: a possible trafficking code in the Kv1 subfamily." Biochemical Journal 388, no. 1 (May 10, 2005): 355–62. http://dx.doi.org/10.1042/bj20041447.

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Kv1.1 and Kv1.4 potassium channels have different pore region determinants that were found to affect their cell-surface levels positively and negatively [Zhu, Watanabe, Gomez and Thornhill (2001) J. Biol. Chem. 276, 39419–39427; Zhu, Watanabe, Gomez and Thornhill (2003) J. Biol. Chem. 278, 25558–25567; Zhu, Watanabe, Gomez and Thornhill (2003) Biochem. J. 375, 761–768]. In the present study, we focused on the deep pore region of Kv1 members to test whether a cell-surface trafficking code was dictated by two amino acids. Kv1 channels with a threonine/lysine amino acid pair in a non-contiguous pore region promoted high surface levels, whereas a serine/tyrosine amino acid pair inhibited high surface expression by inducing a high level of partial endoplasmic reticulum retention. Our work suggests that a possible positive trafficking amino acid pair coding here for the Kv1 subfamily is Thr/Lys>Thr/Val>Thr/Tyr>Thr/Arg∼Thr/His>Ser/Val>Ser/Tyr>Ser/Lys. The Kv1 trafficking code was not transferable to a Kv2 family member and thus it appears that it only governs surface levels in the context of its Kv1 native pore loop region and/or its S5 and S6 regions. All members of a given Kv2, Kv3 or Kv4 potassium channel subfamily have identical amino acids at similar positions in their deep pore regions (Thr/Tyr or Thr/Val), which suggests that any difference in surface levels among members is not dictated by these amino acids. Thus a major determinant for cell-surface trafficking of Kv1 potassium channels is an amino acid pair in their deep pore regions, whereas the cell-surface levels of a given Kv2, Kv3 or Kv4 subfamily member are probably not affected by these amino acids.

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B, Pooja, Govinda Sharma K, and Vinay R. Kadibagil. "Pharmaceutical Modification of Kasisadi Churna to Varti and its Physicochemical Analysis." International Journal of Ayurvedic Medicine 11, no. 3 (October 2, 2020): 470–76. http://dx.doi.org/10.47552/ijam.v11i3.1589.

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Background: Kasisadi churna is a yoga (formulation) mentioned for treatment of kaphaja yoni vyapath (vulvo vaginal candidiasis) which is applied as lepa along with honey. But the administration of the drug through vaginal route in this form is highly discomforting. Modification of a dosage form is essential for the enhancement of efficacy, acceptability of the product and shelf life. Materials and Methods: Varti is prepared from the drugs of kasisadi churna in three methods, bhavana method (KV1), gudapaka method (KV2) and modified method (KV3) with the addition of cocoa butter as base. The prepared samples were tested for analytical parameters. Result and Discussion: Kasisadi churna can be easily modified into varti form. Preparation of KV2 was easy, gives more yield in less time and better in organoleptic features and disintegration time compared to KV1 and KV3. Conclusion: The results of the pharmaceutical and analytical study can be considered as the preliminary standards for the preparation of Kasisadi Varti.

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Bocksteins, Elke. "Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders." Journal of General Physiology 147, no. 2 (January 11, 2016): 105–25. http://dx.doi.org/10.1085/jgp.201511507.

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Members of the electrically silent voltage-gated K+ (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K+ channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.

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Kaczmarek, Leonard K., and Yalan Zhang. "Kv3 Channels: Enablers of Rapid Firing, Neurotransmitter Release, and Neuronal Endurance." Physiological Reviews 97, no. 4 (October 1, 2017): 1431–68. http://dx.doi.org/10.1152/physrev.00002.2017.

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The intrinsic electrical characteristics of different types of neurons are shaped by the K+ channels they express. From among the more than 70 different K+ channel genes expressed in neurons, Kv3 family voltage-dependent K+ channels are uniquely associated with the ability of certain neurons to fire action potentials and to release neurotransmitter at high rates of up to 1,000 Hz. In general, the four Kv3 channels Kv3.1–Kv3.4 share the property of activating and deactivating rapidly at potentials more positive than other channels. Each Kv3 channel gene can generate multiple protein isoforms, which contribute to the high-frequency firing of neurons such as auditory brain stem neurons, fast-spiking GABAergic interneurons, and Purkinje cells of the cerebellum, and to regulation of neurotransmitter release at the terminals of many neurons. The different Kv3 channels have unique expression patterns and biophysical properties and are regulated in different ways by protein kinases. In this review, we cover the function, localization, and modulation of Kv3 channels and describe how levels and properties of the channels are altered by changes in ongoing neuronal activity. We also cover how the protein-protein interaction of these channels with other proteins affects neuronal functions, and how mutations or abnormal regulation of Kv3 channels are associated with neurological disorders such as ataxias, epilepsies, schizophrenia, and Alzheimer’s disease.

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Friederich, Patrick, Dietmar Benzenberg, Sokratis Trellakis, and Bernd W. Urban. "Interaction of Volatile Anesthetics with Human Kv Channels in Relation to Clinical Concentrations." Anesthesiology 95, no. 4 (October 1, 2001): 954–58. http://dx.doi.org/10.1097/00000542-200110000-00026.

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Background Recent evidence shows that inhibition of human Kv3 channels by intravenous anesthetics occurs at clinical concentrations. The effects of volatile anesthetics on these human ion channels are unknown. This study was designed to establish whether minimum alveolar concentrations (MAC) of halothane, enflurane, isoflurane, and desflurane exhibit effects on Kv3 channeLs. To obtain an indication whether these findings may be specific to Kv3 channels, the effects of enflurane and isoflurane on human Kv1.1 channels were also investigated. Methods Kv3 channels natively expressed in SH-SY5Y cells and Kv1.1 channels expressed in HEK293 cells were measured with the whole cell patch clamp technique by standard protocols. Concentrations of volatile anesthetics were determined by gas chromatography. Results Halothane, enflurane, isoflurane, and desflurane reversibly inhibited Kv3 channels in a concentration-dependent manner. Concentrations at half-maximal effect (IC50 values) ranged between 1,800 and 4,600 microM. Hill coefficients were between 1.7 and 2.5. IC50 values for inhibition of Kv1.1 channels were 2,800 and 5,200 microM, and Hill coefficients were 3.9 and 5.6 for enflurane and isoflurane, respectively. Conclusion Volatile anesthetics inhibit human Kv3 channels at clinical concentrations. At 1-3 MAC, inhibition would account on average for 2-12%. Inhibition would be highest with enflurane (between 3% and 22%) and lowest with isoflurane (between 0.2% and 3%). Kv1.1 channels would only be inhibited by enflurane at clinical concentrations (2% at 2 MAC and 8% at 3 MAC). Whether the degree of K channel inhibition by volatile anesthetics may contribute to their clinical action needs further study.

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Klassen, Tara L., Steven D. Buckingham, Donna M. Atherton, Joel B. Dacks, Warren J. Gallin, and Andrew N. Spencer. "Atypical Phenotypes From Flatworm Kv3 Channels." Journal of Neurophysiology 95, no. 5 (May 2006): 3035–46. http://dx.doi.org/10.1152/jn.00858.2005.

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Divergence of the Shaker superfamily of voltage-gated (Kv) ion channels early in metazoan evolution created numerous electrical phenotypes that were presumably selected to produce a wide range of excitability characteristics in neurons, myocytes, and other cells. A comparative approach that emphasizes this early radiation provides a comprehensive sampling of sequence space that is necessary to develop generally applicable models of the structure–function relationship in the Kv potassium channel family. We have cloned and characterized two Shaw-type potassium channels from a flatworm ( Notoplana atomata) that is arguably a representative of early diverging bilaterians. When expressed in Xenopus oocytes, one of these cloned channels, N.at-Kv3.1, exhibits a noninactivating, outward current with slow opening kinetics that are dependent on both the holding potential and the activating potential. A second Shaw-type channel, N.at-Kv3.2, has very different properties, showing weak inward rectification. These results demonstrate that broad phylogenetic sampling of proteins of a single family will reveal unexpected properties that lead to new interpretations of structure–function relationships.

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Pilati, Nadia, Michele Speggiorin, Giuseppe Alvaro, and Charles H. Large. "Pharmacological Modulation of Kv3 Potassium Currents." Biophysical Journal 116, no. 3 (February 2019): 540a. http://dx.doi.org/10.1016/j.bpj.2018.11.2905.

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9

Pisupati, Aditya, Keith J. Mickolajczyk, William Horton, Damian B. van Rossum, Andriy Anishkin, Sree V. Chintapalli, Xiaofan Li, et al. "The S6 gate in regulatory Kv6 subunits restricts heteromeric K+ channel stoichiometry." Journal of General Physiology 150, no. 12 (October 15, 2018): 1702–21. http://dx.doi.org/10.1085/jgp.201812121.

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The Shaker-like family of voltage-gated K+ channels comprises four functionally independent gene subfamilies, Shaker (Kv1), Shab (Kv2), Shaw (Kv3), and Shal (Kv4), each of which regulates distinct aspects of neuronal excitability. Subfamily-specific assembly of tetrameric channels is mediated by the N-terminal T1 domain and segregates Kv1–4, allowing multiple channel types to function independently in the same cell. Typical Shaker-like Kv subunits can form functional channels as homotetramers, but a group of mammalian Kv2-related genes (Kv5.1, Kv6s, Kv8s, and Kv9s) encodes subunits that have a “silent” or “regulatory” phenotype characterized by T1 self-incompatibility. These channels are unable to form homotetramers, but instead heteromerize with Kv2.1 or Kv2.2 to diversify the functional properties of these delayed rectifiers. While T1 self-incompatibility predicts that these heterotetramers could contain up to two regulatory (R) subunits, experiments show a predominance of 3:1R stoichiometry in which heteromeric channels contain a single regulatory subunit. Substitution of the self-compatible Kv2.1 T1 domain into the regulatory subunit Kv6.4 does not alter the stoichiometry of Kv2.1:Kv6.4 heteromers. Here, to identify other channel structures that might be responsible for favoring the 3:1R stoichiometry, we compare the sequences of mammalian regulatory subunits to independently evolved regulatory subunits from cnidarians. The most widespread feature of regulatory subunits is the presence of atypical substitutions in the highly conserved consensus sequence of the intracellular S6 activation gate of the pore. We show that two amino acid substitutions in the S6 gate of the regulatory subunit Kv6.4 restrict the functional stoichiometry of Kv2.1:Kv6.4 to 3:1R by limiting the formation and function of 2:2R heteromers. We propose a two-step model for the evolution of the asymmetric 3:1R stoichiometry, which begins with evolution of self-incompatibility to establish the regulatory phenotype, followed by drift of the activation gate consensus sequence under relaxed selection to limit stoichiometry to 3:1R.

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Ozaita, A., M. E. Martone, M. H. Ellisman, and B. Rudy. "Differential Subcellular Localization of the Two Alternatively Spliced Isoforms of the Kv3.1 Potassium Channel Subunit in Brain." Journal of Neurophysiology 88, no. 1 (July 1, 2002): 394–408. http://dx.doi.org/10.1152/jn.2002.88.1.394.

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Voltage-gated K+ channels containing pore-forming subunits of the Kv3 subfamily have specific roles in the fast repolarization of action potentials and enable neurons to fire repetitively at high frequencies. Each of the four known Kv3 genes encode multiple products by alternative splicing of 3′ ends resulting in the expression of K+ channel subunits differing only in their C-terminal sequence. The alternative splicing does not affect the electrophysiological properties of the channels, and its physiological role is unknown. It has been proposed that one of the functions of the alternative splicing of Kv3 genes is to produce subunit isoforms with differential subcellular membrane localizations in neurons and differential modulation by signaling pathways. We investigated the role of the alternative splicing of Kv3 subunits in subcellular localization by examining the brain distribution of the two alternatively spliced versions of the Kv3.1 gene (Kv3.1a and Kv3.1b) with antibodies specific for the alternative spliced C-termini. Kv3.1b proteins were prominently expressed in the somatic and proximal dendritic membrane of specific neuronal populations in the mouse brain. The axons of most of these neurons also expressed Kv3.1b protein. In contrast, Kv3.1a proteins were prominently expressed in the axons of some of the same neuronal populations, but there was little to no Kv3.1a protein expression in somatodendritic membrane. Exceptions to this pattern were seen in two neuronal populations with unusual targeting of axonal proteins, mitral cells of the olfactory bulb, and mesencephalic trigeminal neurons, which expressed Kv3.1a protein in dendritic and somatic membrane, respectively. The results support the hypothesis that the alternative spliced C-termini of Kv3 subunits regulate their subcellular targeting in neurons.

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Gittis, Aryn H., Setareh H. Moghadam, and Sascha du Lac. "Mechanisms of Sustained High Firing Rates in Two Classes of Vestibular Nucleus Neurons: Differential Contributions of Resurgent Na, Kv3, and BK Currents." Journal of Neurophysiology 104, no. 3 (September 2010): 1625–34. http://dx.doi.org/10.1152/jn.00378.2010.

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To fire at high rates, neurons express ionic currents that work together to minimize refractory periods by ensuring that sodium channels are available for activation shortly after each action potential. Vestibular nucleus neurons operate around high baseline firing rates and encode information with bidirectional modulation of firing rates up to several hundred Hz. To determine the mechanisms that enable these neurons to sustain firing at high rates, ionic currents were measured during firing by using the action potential clamp technique in vestibular nucleus neurons acutely dissociated from transgenic mice. Although neurons from the YFP-16 line fire at rates higher than those from the GIN line, both classes of neurons express Kv3 and BK currents as well as both transient and resurgent Na currents. In the fastest firing neurons, Kv3 currents dominated repolarization at all firing rates and minimized Na channel inactivation by rapidly transitioning Na channels from the open to the closed state. In slower firing neurons, BK currents dominated repolarization at the highest firing rates and sodium channel availability was protected by a resurgent blocking mechanism. Quantitative differences in Kv3 current density across neurons and qualitative differences in immunohistochemically detected expression of Kv3 subunits could account for the difference in firing range within and across cell classes. These results demonstrate how divergent firing properties of two neuronal populations arise through the interplay of at least three ionic currents.

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Möller, Lena, Glenn Regnier, Alain J. Labro, Rikard Blunck, and Dirk J. Snyders. "Determining the correct stoichiometry of Kv2.1/Kv6.4 heterotetramers, functional in multiple stoichiometrical configurations." Proceedings of the National Academy of Sciences 117, no. 17 (April 13, 2020): 9365–76. http://dx.doi.org/10.1073/pnas.1916166117.

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The electrically silent (KvS) members of the voltage-gated potassium (Kv) subfamilies Kv5, Kv6, Kv8, and Kv9 selectively modulate Kv2 subunits by forming heterotetrameric Kv2/KvS channels. Based on the reported 3:1 stoichiometry of Kv2.1/Kv9.3 channels, we tested the hypothesis that Kv2.1/Kv6.4 channels express, in contrast to the assumed 3:1, in a 2:2 stoichiometry. We investigate the Kv2.1/Kv6.4 stoichiometry using single subunit counting and functional characterization of tetrameric concatemers. For selecting the most probable stoichiometry, we introduce a model-selection method that is applicable for any multimeric complex by investigating the stoichiometry of Kv2.1/Kv6.4 channels. Weighted likelihood calculations bring rigor to a powerful technique. Using the weighted-likelihood model-selection method and analysis of electrophysiological data, we show that Kv2.1/Kv6.4 channels express, in contrast to the assumed 3:1, in a 2:2 stoichiometry. Within this stoichiometry, the Kv6.4 subunits have to be positioned alternating with Kv2.1 to express functional channels. The variability in Kv2/KvS assembly increases the diversity of heterotetrameric configurations and extends the regulatory possibilities of KvS by allowing the presence of more than one silent subunit.

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RUDY, BERNARDO, ALAN CHOW, DAVID LAU, YIMY AMARILLO, ANDER OZAITA, MICHAEL SAGANICH, HERMAN MORENO, et al. "Contributions of Kv3 Channels to Neuronal Excitability." Annals of the New York Academy of Sciences 868, no. 1 MOLECULAR AND (April 1999): 304–43. http://dx.doi.org/10.1111/j.1749-6632.1999.tb11295.x.

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Meneses, David, Ana V. Vega, Francisco Miguel Torres-Cruz, and Jaime Barral. "KV1 and KV3 Potassium Channels Identified at Presynaptic Terminals of the Corticostriatal Synapses in Rat." Neural Plasticity 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/8782518.

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In the last years it has been increasingly clear thatKV-channel activity modulates neurotransmitter release. The subcellular localization and composition of potassium channels are crucial to understanding its influence on neurotransmitter release. To investigate the role ofKVin corticostriatal synapses modulation, we combined extracellular recording of population-spike and pharmacological blockage with specific and nonspecific blockers to identify several families ofKVchannels. We induced paired-pulse facilitation (PPF) and studied the changes in paired-pulse ratio (PPR) before and after the addition of specificKVblockers to determine whether particularKVsubtypes were located pre- or postsynaptically. Initially, the presence ofKVchannels was tested by exposing brain slices to tetraethylammonium or 4-aminopyridine; in both cases we observed a decrease in PPR that was dose dependent. Further experiments with tityustoxin, margatoxin, hongotoxin, agitoxin, dendrotoxin, and BDS-I toxins all rendered a reduction in PPR. In contrast heteropodatoxin and phrixotoxin had no effect. Our results reveal that corticostriatal presynapticKVchannels have a complex stoichiometry, including heterologous combinationsKV1.1,KV1.2,KV1.3, andKV1.6 isoforms, as well asKV3.4, but notKV4 channels. The variety ofKVchannels offers a wide spectrum of possibilities to regulate neurotransmitter release, providing fine-tuning mechanisms to modulate synaptic strength.

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Ishikawa, Taro, Yukihiro Nakamura, Naoto Saitoh, Wen-Bin Li, Shinichi Iwasaki, and Tomoyuki Takahashi. "Distinct Roles of Kv1 and Kv3 Potassium Channels at the Calyx of Held Presynaptic Terminal." Journal of Neuroscience 23, no. 32 (November 12, 2003): 10445–53. http://dx.doi.org/10.1523/jneurosci.23-32-10445.2003.

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Marom, S., and I. B. Levitan. "State-dependent inactivation of the Kv3 potassium channel." Biophysical Journal 67, no. 2 (August 1994): 579–89. http://dx.doi.org/10.1016/s0006-3495(94)80517-x.

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Issa, Fadi A., M. Kristen Hall, Cody J. Hatchett, Douglas A. Weidner, Alexandria C. Fiorenza, and Ruth A. Schwalbe. "Compromised N-Glycosylation Processing of Kv3.1b Correlates with Perturbed Motor Neuron Structure and Locomotor Activity." Biology 10, no. 6 (May 30, 2021): 486. http://dx.doi.org/10.3390/biology10060486.

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Neurological difficulties commonly accompany individuals suffering from congenital disorders of glycosylation, resulting from defects in the N-glycosylation pathway. Vacant N-glycosylation sites (N220 and N229) of Kv3, voltage-gated K+ channels of high-firing neurons, deeply perturb channel activity in neuroblastoma (NB) cells. Here we examined neuron development, localization, and activity of Kv3 channels in wildtype AB zebrafish and CRISPR/Cas9 engineered NB cells, due to perturbations in N-glycosylation processing of Kv3.1b. We showed that caudal primary (CaP) motor neurons of zebrafish spinal cord transiently expressing fully glycosylated (WT) Kv3.1b have stereotypical morphology, while CaP neurons expressing partially glycosylated (N220Q) Kv3.1b showed severe maldevelopment with incomplete axonal branching and extension around the ventral musculature. Consequently, larvae expressing N220Q in CaP neurons had impaired swimming locomotor activity. We showed that replacement of complex N-glycans with oligomannose attached to Kv3.1b and at cell surface lessened Kv3.1b dispersal to outgrowths by altering the number, size, and density of Kv3.1b-containing particles in membranes of rat neuroblastoma cells. Opening and closing rates were slowed in Kv3 channels containing Kv3.1b with oligomannose, instead of complex N-glycans, which suggested a reduction in the intrinsic dynamics of the Kv3.1b α-subunit. Thus, N-glycosylation processing of Kv3.1b regulates neuronal development and excitability, thereby controlling motor activity.

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Schwalbe, Ruth A., Melissa J. Corey, and Tara A. Cartwright. "Novel Kv3 glycoforms differentially expressed in adult mammalian brain contain sialylated N-glycans." Biochemistry and Cell Biology 86, no. 1 (February 2008): 21–30. http://dx.doi.org/10.1139/o07-152.

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The N-glycan pool of mammalian brain contains remarkably high levels of sialylated N-glycans. This study provides the first evidence that voltage-gated K+ channels Kv3.1, Kv3.3, and Kv3.4, possess distinct sialylated N-glycan structures throughout the central nervous system of the adult rat. Electrophoretic migration patterns of Kv3.1, Kv3.3, and Kv3.4 glycoproteins from spinal cord, hypothalamus, thalamus, cerebral cortex, hippocampus, and cerebellum membranes digested with glycosidases were used to identify the various glycoforms. Differences in the migration of Kv3 proteins were attributed to the desialylated N-glycans. Expression levels of the Kv3 proteins were highest in cerebellum, whereas those of Kv3.1 and Kv3.3 were much lower in the other 5 regions. The lowest level of Kv3.1 was expressed in the hypothalamus, whereas the lowest levels of Kv3.3 were expressed in both thalamus and hypothalamus. The other regions expressed intermediate levels of Kv3.3, with spinal cord expressing the highest. The expression level of Kv3.4 in the hippocampus was slightly lower than that in cerebellum, and was closely followed by the other 4 regions, with spinal cord expressing the lowest level. We suggest that novel Kv3 glycoforms may endow differences in channel function and expression among regions throughout the central nervous system.

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Wang, Jian, Letitia Weigand, Wenqian Wang, J. T. Sylvester, and Larissa A. Shimoda. "Chronic hypoxia inhibits Kv channel gene expression in rat distal pulmonary artery." American Journal of Physiology-Lung Cellular and Molecular Physiology 288, no. 6 (June 2005): L1049—L1058. http://dx.doi.org/10.1152/ajplung.00379.2004.

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In pulmonary arterial smooth muscle cells (PASMCs), voltage-gated K+ (Kv) channels play an important role in regulating membrane potential, cytoplasmic free Ca2+ concentration, and pulmonary vasomotor tone. Previous studies demonstrated that exposure of rats to chronic hypoxia decreased Kv channel function in PASMCs from distal pulmonary arteries (dPA). To determine whether this decrease in function was due to decreased expression of Kv channel proteins and which Kv proteins might be involved, we analyzed Kv channel gene expression in intact, endothelium-denuded dPAs obtained from rats exposed to 10% O2 for 3 wk. Kv1.1, Kv1.2, Kv1.4, Kv1.5, Kv1.6, Kv2.1, Kv3.1, Kv4.3, and Kv9.3 channel α-subunits and Kv1, Kv2, and Kv3 β-subunits were expressed in rat dPAs. Exposure to chronic hypoxia decreased mRNA and protein levels of Kv1.1, Kv1.5, Kv1.6, Kv2.1, and Kv4.3 α-subunits in dPAs but did not alter gene or protein expression of these channels in aorta. Furthermore, chronic hypoxia did not alter the mRNA levels of β-subunits in dPAs. These results suggest that diminished transcription of Kv α-subunits may reduce the number of functional Kv channels in dPAs during prolonged hypoxia, causing the decreased Kv current previously observed in PASMCs and leading to pulmonary artery vasoconstriction.

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Regnier, Glenn, Elke Bocksteins, Waleed F. Marei, Isabel Pintelon, Jean-Pierre Timmermans, Jo L. M. R. Leroy, and Dirk J. Snyders. "Targeted deletion of the Kv6.4 subunit causes male sterility due to disturbed spermiogenesis." Reproduction, Fertility and Development 29, no. 8 (2017): 1567. http://dx.doi.org/10.1071/rd16075.

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Electrically silent voltage-gated potassium (KvS) channel subunits (i.e. Kv5–Kv6 and Kv8–Kv9) do not form functional homotetrameric Kv channels, but co-assemble with Kv2 subunits, generating functional heterotetrameric Kv2–KvS channel complexes in which the KvS subunits modulate the Kv2 channel properties. Several KvS subunits are expressed in testis tissue but knowledge about their contribution to testis physiology is lacking. Here, we report that the targeted deletion of Kv6.4 in a transgenic mouse model (Kcng4–/–) causes male sterility as offspring from homozygous females were only obtained after mating with wild-type (WT) or heterozygous males. Semen quality analysis revealed that the sterility of the homozygous males was caused by a severe reduction in total sperm-cell count and the absence of motile spermatozoa in the semen. Furthermore, spermatozoa of homozygous mice showed an abnormal morphology characterised by a smaller head and a shorter tail compared with WT spermatozoa. Comparison of WT and Kcng4–/– testicular tissue indicated that this inability to produce (normal) spermatozoa was due to disturbed spermiogenesis. These results suggest that Kv6.4 subunits are involved in the regulation of the late stages of spermatogenesis, which makes them a potentially interesting pharmacological target for the development of non-hormonal male contraceptives.

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Martina, Marco, Alexia E. Metz, and Bruce P. Bean. "Voltage-Dependent Potassium Currents During Fast Spikes of Rat Cerebellar Purkinje Neurons: Inhibition by BDS-I Toxin." Journal of Neurophysiology 97, no. 1 (January 2007): 563–71. http://dx.doi.org/10.1152/jn.00269.2006.

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We characterized the kinetics and pharmacological properties of voltage-activated potassium currents in rat cerebellar Purkinje neurons using recordings from nucleated patches, which allowed high resolution of activation and deactivation kinetics. Activation was exceptionally rapid, with 10–90% activation in about 400 μs at +30 mV, near the peak of the spike. Deactivation was also extremely rapid, with a decay time constant of about 300 μs near −80 mV. These rapid activation and deactivation kinetics are consistent with mediation by Kv3-family channels but are even faster than reported for Kv3-family channels in other neurons. The peptide toxin BDS-I had very little blocking effect on potassium currents elicited by 100-ms depolarizing steps, but the potassium current evoked by action potential waveforms was inhibited nearly completely. The mechanism of inhibition by BDS-I involves slowing of activation rather than total channel block, consistent with the effects described in cloned Kv3-family channels and this explains the dramatically different effects on currents evoked by short spikes versus voltage steps. As predicted from this mechanism, the effects of toxin on spike width were relatively modest (broadening by roughly 25%). These results show that BDS-I–sensitive channels with ultrafast activation and deactivation kinetics carry virtually all of the voltage-dependent potassium current underlying repolarization during normal Purkinje cell spikes.

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Sim, Hun Ju, and So Yeong Lee. "Kv3 channels Modulate Epithelial Mesenchymal Transition through Akt pathway." FASEB Journal 34, S1 (April 2020): 1. http://dx.doi.org/10.1096/fasebj.2020.34.s1.04991.

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Parekh, Puja K., Michelle M. Sidor, Andrea Gillman, Darius Becker-Krail, Letizia Bettelini, Roberto Arban, Giuseppe S. Alvaro, et al. "Antimanic Efficacy of a Novel Kv3 Potassium Channel Modulator." Neuropsychopharmacology 43, no. 2 (August 31, 2017): 435–44. http://dx.doi.org/10.1038/npp.2017.155.

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Cartwright, Tara A., and Ruth A. Schwalbe. "Atypical sialylated N-glycan structures are attached to neuronal voltage-gated potassium channels." Bioscience Reports 29, no. 5 (June 15, 2009): 301–13. http://dx.doi.org/10.1042/bsr20080149.

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Mammalian brains contain relatively high amounts of common and uncommon sialylated N-glycan structures. Sialic acid linkages were identified for voltage-gated potassium channels, Kv3.1, 3.3, 3.4, 1.1, 1.2 and 1.4, by evaluating their electrophoretic migration patterns in adult rat brain membranes digested with various glycosidases. Additionally, their electrophoretic migration patterns were compared with those of NCAM (neural cell adhesion molecule), transferrin and the Kv3.1 protein heterologously expressed in B35 neuroblastoma cells. Metabolic labelling of the carbohydrates combined with glycosidase digestion reactions were utilized to show that the N-glycan of recombinant Kv3.1 protein was capped with an oligo/poly-sialyl unit. All three brain Kv3 glycoproteins, like NCAM, were terminated with α2,3-linked sialyl residues, as well as atypical α2,8-linked sialyl residues. Additionally, at least one of their antennae was terminated with an oligo/poly-sialyl unit, similar to recombinant Kv3.1 and NCAM. In contrast, brain Kv1 glycoproteins consisted of sialyl residues with α2,8-linkage, as well as sialyl residues linked to internal carbohydrate residues of the carbohydrate chains of the N-glycans. This type of linkage was also supported for Kv3 glycoproteins. To date, such a sialyl linkage has only been identified in gangliosides, not N-linked glycoproteins. We conclude that all six Kv channels (voltage-gated K+ channels) contribute to the α2,8-linked sialylated N-glycan pool in mammalian brain and furthermore that their N-glycan structures contain branched sialyl residues. Identification of these novel and unique sialylated N-glycan structures implicate a connection between potassium channel activity and atypical sialylated N-glycans in modulating and fine-tuning the excitable properties of neurons in the nervous system.

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Hoshi, Hiroaki, Hiroto Kuwabara, Gabriel Léger, Paul Cumming, Mark Guttman, and Albert Gjedde. "6-[18F]fluoro-l-DOPA Metabolism in Living Human Brain: A Comparison of Six Analytical Methods." Journal of Cerebral Blood Flow & Metabolism 13, no. 1 (January 1993): 57–69. http://dx.doi.org/10.1038/jcbfm.1993.8.

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In 11 normal volunteers and six patients with Parkinson's disease, we compared six different analyses of dopaminergic function with l-3,4-dihydroxy-6-[18F]fluorophenylalanine (FDOPA) and positron emission tomography (PET). The caudate nucleus, putamen, and several reference regions were identified in PET images, using magnetic resonance imaging (MRI). The six analyses included two direct determinations of DOPA decarboxylase activity ( kD3, k*3), the slope–intercept plot based on plasma concentration ( K), two slope–intercept plots based on tissue content ( kr3, ks3), and the striato–occipital ratio [ R( T)]. For all analyses, the difference between two groups of subjects (normal volunteers and patients with Parkinson's disease) was larger in the putamen than in the caudate. For the caudate nucleus, the DOPA decarboxylase activity ( kD3, k*3), tissue slope–intercept plots ( kr3, ks3), and striato–occipital ratio [ R( T)] analyses significantly discriminated between the normal volunteers and the patients with Parkinson's disease ( p < 0.005) [with least significance for k*3 ( p < 0.05)], while the plasma slope–intercept plot ( K) failed to do so. For the putamen, the values for kD3, k*3, K, kr3, ks3 and R( T) of normal volunteers were significantly higher than those of patients ( p < 0.005) [with least significance for K ( p < 0.025)]. Linear correlations were significant between kD3 and ks3; kD3 and kr3; kD3 and R( T); and kD3 and k*3, in this order of significance. We found no correlation between kD3 and K values in the caudate nucleus.

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Sim, Hun Ju, Min Seok Song, and So Yeong Lee. "Kv3 channels contribute to cancer cell migration via vimentin regulation." Biochemical and Biophysical Research Communications 551 (April 2021): 140–47. http://dx.doi.org/10.1016/j.bbrc.2021.03.019.

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Joho, R. H., C. Street, S. Matsushita, and T. Knopfel. "Behavioral motor dysfunction in Kv3-type potassium channel-deficient mice." Genes, Brain and Behavior 5, no. 6 (August 2006): 472–82. http://dx.doi.org/10.1111/j.1601-183x.2005.00184.x.

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Sacco, Tiziana, Annarita De Luca, and Filippo Tempia. "Properties and expression of Kv3 channels in cerebellar Purkinje cells." Molecular and Cellular Neuroscience 33, no. 2 (October 2006): 170–79. http://dx.doi.org/10.1016/j.mcn.2006.07.006.

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Song, Min Seok, Hun Ju Sim, Seonmi Kang, Sangwan Park, Kangmoon Seo, and So Yeong Lee. "Pharmacological inhibition of Kv3 on oxidative stress-induced cataract progression." Biochemical and Biophysical Research Communications 533, no. 4 (December 2020): 1255–61. http://dx.doi.org/10.1016/j.bbrc.2020.09.138.

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Shevchenko, Talent, Ryoichi Teruyama, and William E. Armstrong. "High-Threshold, Kv3-Like Potassium Currents in Magnocellular Neurosecretory Neurons and Their Role in Spike Repolarization." Journal of Neurophysiology 92, no. 5 (November 2004): 3043–55. http://dx.doi.org/10.1152/jn.00431.2004.

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We identified Kv3-like high-threshold K+ currents in hypothalamic supraoptic neurons using whole cell recordings in hypothalamic slices and in acutely dissociated neurons. Tetraethylammonium (TEA)-sensitive currents (<1 mM TEA) evoked from −50 mV were characterized by a large component that inactivated in 10–30 ms, and a smaller, persistent component that inactivated in 1–2 s. I/ V relations in dissociated neurons revealed TEA-subtracted currents with a slope and voltage dependency consistent with the presence of Kv3-like channels. In slices, tests with 0.01–0.7 mM TEA produced an IC50 of 200–300 nM for both fast and persistent currents. The fast transient current was similar to currents associated with the expression of Kv3.4 subunits, given that it was sensitive to BDS-I (100 nM). The persistent TEA-sensitive current appeared similar to those attributed to Kv3.1/3.2 subunits. Although qualitatively similar, oxytocin (OT) and vasopressin (VP) neurons in slices differed in the stronger presence of persistent current in VP neurons. In both cell types, the IC50 for TEA-induced spike broadening was similar to that observed for current suppression in voltage clamp. However, TEA had a greater effect on the spike width of VP neurons than of OT neurons. Immunochemical studies revealed a stronger expression of the Kv3.1b α-subunit in VP neurons, which may be related to the greater importance of this current type in VP spike repolarization. Because OT and VP neurons are not considered fast firing, but do exhibit frequency- and calcium-dependent spike broadening, Kv3-like currents may be important for maintaining spike width and calcium influx within acceptable limits during repetitive firing.

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Escobar, Laura I., Julio C. Martínez-Téllez, Monica Salas, Salvador A. Castilla, Rolando Carrisoza, Dagoberto Tapia, Mario Vázquez, José Bargas, and Juan J. Bolívar. "A voltage-gated K+ current in renal inner medullary collecting duct cells." American Journal of Physiology-Cell Physiology 286, no. 4 (April 2004): C965—C974. http://dx.doi.org/10.1152/ajpcell.00074.2003.

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We studied the K+-selective conductances in primary cultures of rat renal inner medullary collecting duct (IMCD) using perforated-patch and conventional whole cell techniques. Depolarizations above –20 mV induced a time-dependent outward K+ current ( Ivto) similar to a delayed rectifier. Ivto showed a half-maximal activation around 5.6 mV with a slope factor of 6.8 mV. Its K+/Na+ selectivity ratio was 11.7. It was inhibited by tetraethylammonium, quinidine, 4-aminopyridine, and Ba2+ and was not Ca2+ dependent. The delayed rectifying characteristics of Ivto prompted us to screen the expression of Kv1 and Kv3 families by RT-PCR. Analysis of RNA isolated from cell cultures revealed the presence of three Kv α-subunits (Kv1.1, Kv1.3, and Kv1.6). Western blot analysis with Kv α-subunit antibodies for Kv1.1 and Kv1.3 showed labeling of ∼70-kDa proteins from inner medulla plasmatic and microsome membranes. Immunocytochemical analysis of cell culture and kidney inner medulla showed that Kv1.3 is colocalized with the Na+-K+-ATPase at the basolateral membrane, although it is also in the cytoplasm. This is the first evidence of recording, protein expression, and localization of a voltage-gated Kv1 in the kidney IMCD cells.

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McKay, B. E., and R. W. Turner. "Kv3 K+ channels enable burst output in rat cerebellar Purkinje cells." European Journal of Neuroscience 20, no. 3 (August 2004): 729–39. http://dx.doi.org/10.1111/j.1460-9568.2004.03539.x.

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Large, Charles, Daniela Cardinu, Mike Harte, Tamara Modebadze, Fiona LeBeau, Giuseppe Alvaro, Mark Cunningham, and Joanne Neill. "77. Enhancing PV Interneuron Function through Targeted Modulation of Kv3 Channels." Biological Psychiatry 81, no. 10 (May 2017): S32. http://dx.doi.org/10.1016/j.biopsych.2017.02.089.

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Bekar, Lane K., Matthew E. Loewen, Kun Cao, Xianfeng Sun, Jerome Leis, Rui Wang, George W. Forsyth, and Wolfgang Walz. "Complex Expression and Localization of Inactivating Kv Channels in Cultured Hippocampal Astrocytes." Journal of Neurophysiology 93, no. 3 (March 2005): 1699–709. http://dx.doi.org/10.1152/jn.00850.2004.

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Voltage-gated potassium channels are well established as critical for setting action potential frequency, membrane potential, and neurotransmitter release in neurons. However, their role in the “nonexcitable” glial cell type is yet to be fully understood. We used whole cell current kinetics, pharmacology, immunocytochemistry, and RT-PCR to characterize A-type current in hippocampal astrocyte cultures to better understand its function. Pharmacological analysis suggests that ∼70, 10, and <5% of total A current is associated with Kv4, Kv3, and Kv1 channels, respectively. In addition, pharmacology and kinetics provide evidence for a significant contribution of KChIP accessory proteins to astrocytic A-channel composition. Localization of the Shaw Kv3.4 channel to astrocytic processes and the Shal Kv4.3 channel to soma suggest that these channels serve a specific function. Given this complex A-type channel expression pattern, we assessed the role of A currents in membrane voltage oscillations in response to current injections. Although TEA-sensitive delayed-rectifying currents are involved in the extent of repolarization, 4-AP-sensitive A currents serve to increase the rate. As in neurons, this effect may enable astrocytes to respond rapidly to high-frequency synaptic events. Our results indicate that hippocampal astrocytes in vitro express multiple A-type Kv channel α-subunits with accessory, possibly Ca2+-sensitive, cytoplasmic subunits that appear to be specifically localized to subcellular membrane compartments. Function of these channels remains to be determined in a physiological setting. However, this study suggests that they enable astrocytes to respond rapidly with membrane voltage oscillations to high-frequency incoming signals, possibly synchronizing astrocyte function to neuronal activity.

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McGahon, Mary K., Jennine M. Dawicki, Aruna Arora, D. A. Simpson, T. A. Gardiner, A. W. Stitt, C. Norman Scholfield, J. Graham McGeown, and Tim M. Curtis. "Kv1.5 is a major component underlying the A-type potassium current in retinal arteriolar smooth muscle." American Journal of Physiology-Heart and Circulatory Physiology 292, no. 2 (February 2007): H1001—H1008. http://dx.doi.org/10.1152/ajpheart.01003.2006.

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Little is known about the molecular characteristics of the voltage-activated K+ (Kv) channels that underlie the A-type K+ current in vascular smooth muscle cells of the systemic circulation. We investigated the molecular identity of the A-type K+ current in retinal arteriolar myocytes using patch-clamp techniques, RT-PCR, immunohistochemistry, and neutralizing antibody studies. The A-type K+ current was resistant to the actions of specific inhibitors for Kv3 and Kv4 channels but was blocked by the Kv1 antagonist correolide. No effects were observed with pharmacological agents against Kv1.1/2/3/6 and 7 channels, but the current was partially blocked by riluzole, a Kv1.4 and Kv1.5 inhibitor. The current was not altered by the removal of extracellular K+ but was abolished by flecainide, indicative of Kv1.5 rather than Kv1.4 channels. Transcripts encoding Kv1.5 and not Kv1.4 were identified in freshly isolated retinal arterioles. Immunofluorescence labeling confirmed a lack of Kv1.4 expression and revealed Kv1.5 to be localized to the plasma membrane of the arteriolar smooth muscle cells. Anti-Kv1.5 antibody applied intracellularly inhibited the A-type K+ current, whereas anti-Kv1.4 antibody had no effect. Co-expression of Kv1.5 with Kvβ1 or Kvβ3 accessory subunits is known to transform Kv1.5 currents from delayed rectifers into A-type currents. Kvβ1 mRNA expression was detected in retinal arterioles, but Kvβ3 was not observed. Kvβ1 immunofluorescence was detected on the plasma membrane of retinal arteriolar myocytes. The findings of this study suggest that Kv1.5, most likely co-assembled with Kvβ1 subunits, comprises a major component underlying the A-type K+ current in retinal arteriolar smooth muscle cells.

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Rudy, Bernardo, and Chris J. McBain. "Kv3 channels: voltage-gated K+ channels designed for high-frequency repetitive firing." Trends in Neurosciences 24, no. 9 (September 2001): 517–26. http://dx.doi.org/10.1016/s0166-2236(00)01892-0.

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Friederich, P., D. Benzenberg, and B. W. Urban. "Bupivacaine inhibits human neuronal Kv3 channels in SH‐SY5Y human neuroblastoma cells." British Journal of Anaesthesia 88, no. 6 (June 2002): 864–66. http://dx.doi.org/10.1093/bja/88.6.864.

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Joho, Rolf H., and Edward C. Hurlock. "The Role of Kv3-type Potassium Channels in Cerebellar Physiology and Behavior." Cerebellum 8, no. 3 (February 27, 2009): 323–33. http://dx.doi.org/10.1007/s12311-009-0098-4.

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Silverå Ejneby, Malin, Björn Wallner, and Fredrik Elinder. "Coupling stabilizers open KV1-type potassium channels." Proceedings of the National Academy of Sciences 117, no. 43 (October 13, 2020): 27016–21. http://dx.doi.org/10.1073/pnas.2007965117.

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The opening and closing of voltage-gated ion channels are regulated by voltage sensors coupled to a gate that controls the ion flux across the cellular membrane. Modulation of any part of gating constitutes an entry point for pharmacologically regulating channel function. Here, we report on the discovery of a large family of warfarin-like compounds that open the two voltage-gated type 1 potassium (KV1) channels KV1.5 and Shaker, but not the related KV2-, KV4-, or KV7-type channels. These negatively charged compounds bind in the open state to positively charged arginines and lysines between the intracellular ends of the voltage-sensor domains and the pore domain. This mechanism of action resembles that of endogenous channel-opening lipids and opens up an avenue for the development of ion-channel modulators.

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Pathak, Dhruba, Dongxu Guan, and Robert C. Foehring. "Roles of specific Kv channel types in repolarization of the action potential in genetically identified subclasses of pyramidal neurons in mouse neocortex." Journal of Neurophysiology 115, no. 5 (May 1, 2016): 2317–29. http://dx.doi.org/10.1152/jn.01028.2015.

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The action potential (AP) is a fundamental feature of excitable cells that serves as the basis for long-distance signaling in the nervous system. There is considerable diversity in the appearance of APs and the underlying repolarization mechanisms in different neuronal types (reviewed in Bean BP. Nat Rev Neurosci 8: 451–465, 2007), including among pyramidal cell subtypes. In the present work, we used specific pharmacological blockers to test for contributions of Kv1, Kv2, or Kv4 channels to repolarization of single APs in two genetically defined subpopulations of pyramidal cells in layer 5 of mouse somatosensory cortex ( etv1 and glt) as well as pyramidal cells from layer 2/3. These three subtypes differ in AP properties (Groh A, Meyer HS, Schmidt EF, Heintz N, Sakmann B, Krieger P. Cereb Cortex 20: 826–836, 2010; Guan D, Armstrong WE, Foehring RC. J Neurophysiol 113: 2014–2032, 2015) as well as laminar position, morphology, and projection targets. We asked what the roles of Kv1, Kv2, and Kv4 channels are in AP repolarization and whether the underlying mechanisms are pyramidal cell subtype dependent. We found that Kv4 channels are critically involved in repolarizing neocortical pyramidal cells. There are also pyramidal cell subtype-specific differences in the role for Kv1 channels. Only Kv4 channels were involved in repolarizing the narrow APs of glt cells. In contrast, in etv1 cells and layer 2/3 cells, the broader APs are partially repolarized by Kv1 channels in addition to Kv4 channels. Consistent with their activation in the subthreshold range, Kv1 channels also regulate AP voltage threshold in all pyramidal cell subtypes.

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Guan, D., M. H. Higgs, L. R. Horton, W. J. Spain, and R. C. Foehring. "Contributions of Kv7-mediated potassium current to sub- and suprathreshold responses of rat layer II/III neocortical pyramidal neurons." Journal of Neurophysiology 106, no. 4 (October 2011): 1722–33. http://dx.doi.org/10.1152/jn.00211.2011.

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After block of Kv1- and Kv2-mediated K+ currents in acutely dissociated neocortical pyramidal neurons from layers II/III of rat somatosensory and motor cortex, the remaining current is slowly activating and persistent. We used whole cell voltage clamp to show that the Kv7 blockers linopirdine and XE-991 blocked a current with similar kinetics to the current remaining after combined block of Kv1 and Kv2 channels. This current was sensitive to low doses of linopirdine and activated more slowly and at more negative potentials than Kv1- or Kv2-mediated current. The Kv7-mediated current decreased in amplitude with time in whole cell recordings, but in most cells the current was stable for several minutes. Current in response to a traditional M-current protocol was blocked by muscarine, linopirdine, and XE-991. Whole cell slice recordings revealed that the Q10 for channel deactivation was ∼2.5. Sharp electrode current-clamp recordings from adult pyramidal cells demonstrated that block of Kv7-mediated current with XE-991 reduced rheobase, shortened the latency to firing to near rheobase current, induced more regular firing at low current intensity, and increased the rate of firing to a given current injection. XE-991 did not affect single action potentials or spike frequency adaptation. Application of XE-991 also eliminated subthreshold voltage oscillations and increased gain for low-frequency inputs (<10 Hz) without affecting gain for higher frequency inputs. These data suggest important roles for Kv7 channels in subthreshold regulation of excitability, generation of theta-frequency subthreshold oscillations, regulation of interspike intervals, and biasing selectivity toward higher frequency inputs.

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42

Ding, Shengyuan, Shannon G. Matta, and Fu-Ming Zhou. "Kv3-Like Potassium Channels Are Required for Sustained High-Frequency Firing in Basal Ganglia Output Neurons." Journal of Neurophysiology 105, no. 2 (February 2011): 554–70. http://dx.doi.org/10.1152/jn.00707.2010.

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The GABA projection neurons in the substantial nigra pars reticulata (SNr) are key output neurons of the basal ganglia motor control circuit. These neurons fire sustained high-frequency, short-duration spikes that provide a tonic inhibition to their targets and are critical to movement control. We hypothesized that a robust voltage-activated K+ conductance that activates quickly and resists inactivation is essential to the remarkable fast-spiking capability in these neurons. Semi-quantitative RT-PCR (qRT-PCR) analysis on laser capture-microdissected nigral neurons indicated that mRNAs for Kv3.1 and Kv3.4, two key subunits for forming high activation threshold, fast-activating, slow-inactivating, 1 mM tetraethylammonium (TEA)-sensitive, fast delayed rectifier ( IDR-fast) type Kv channels, are more abundant in fast-spiking SNr GABA neurons than in slow-spiking nigral dopamine neurons. Nucleated patch clamp recordings showed that SNr GABA neurons have a strong Kv3-like IDR-fast current sensitive to 1 mM TEA that activates quickly at depolarized membrane potentials and is resistant to inactivation. IDR-fast is smaller in nigral dopamine neurons. Pharmacological blockade of IDR-fast by 1 mM TEA impaired the high-frequency firing capability in SNr GABA neurons. Taken together, these results indicate that Kv3-like channels mediating fast-activating, inactivation-resistant IDR-fast current are critical to the sustained high-frequency firing in SNr GABA projection neurons and hence movement control.

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Sciamanna, Giuseppe, and Charles J. Wilson. "The ionic mechanism of gamma resonance in rat striatal fast-spiking neurons." Journal of Neurophysiology 106, no. 6 (December 2011): 2936–49. http://dx.doi.org/10.1152/jn.00280.2011.

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Striatal fast-spiking (FS) cells in slices fire in the gamma frequency range and in vivo are often phase-locked to gamma oscillations in the field potential. We studied the firing patterns of these cells in slices from rats ages 16–23 days to determine the mechanism of their gamma resonance. The resonance of striatal FS cells was manifested as a minimum frequency for repetitive firing. At rheobase, cells fired a doublet of action potentials or doublets separated by pauses, with an instantaneous firing rate averaging 44 spikes/s. The minimum rate for sustained firing was also responsible for the stuttering firing pattern. Firing rate adapted during each episode of firing, and bursts were terminated when firing was reduced to the minimum sustainable rate. Resonance and stuttering continued after blockade of Kv3 current using tetraethylammonium (0.1–1 mM). Both gamma resonance and stuttering were strongly dependent on Kv1 current. Blockade of Kv1 channels with dendrotoxin-I (100 nM) completely abolished the stuttering firing pattern, greatly lowered the minimum firing rate, abolished gamma-band subthreshold oscillations, and slowed spike frequency adaptation. The loss of resonance could be accounted for by a reduction in potassium current near spike threshold and the emergence of a fixed spike threshold. Inactivation of the Kv1 channel combined with the minimum firing rate could account for the stuttering firing pattern. The resonant properties conferred by this channel were shown to be adequate to account for their phase-locking to gamma-frequency inputs as seen in vivo.

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Wu, Xin-Sheng, Shobana Subramanian, Yalan Zhang, Bo Shi, Jessica Xia, Tiansheng Li, Xiaoli Guo, et al. "Presynaptic Kv3 channels are required for fast and slow endocytosis of synaptic vesicles." Neuron 109, no. 6 (March 2021): 938–46. http://dx.doi.org/10.1016/j.neuron.2021.01.006.

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Espinosa, F., G. Marks, N. Heintz, and R. H. Joho. "Increased motor drive and sleep loss in mice lacking Kv3-type potassium channels." Genes, Brain and Behavior 3, no. 2 (April 2004): 90–100. http://dx.doi.org/10.1046/j.1601-183x.2003.00054.x.

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Sand, R. M., D. M. Atherton, A. N. Spencer, and W. J. Gallin. "jShaw1, a low-threshold, fast-activating Kv3 from the hydrozoan jellyfish Polyorchis penicillatus." Journal of Experimental Biology 214, no. 18 (August 24, 2011): 3124–37. http://dx.doi.org/10.1242/jeb.057000.

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Lamont, M. "An electrophysiological analysis of deep cerebellar nuclei, with particular focus on Kv3 channels." Bioscience Horizons 2, no. 1 (February 17, 2009): 55–63. http://dx.doi.org/10.1093/biohorizons/hzp010.

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Brooke, Ruth E., Thomas S. Moores, Neil P. Morris, Simon H. Parson, and Jim Deuchars. "Kv3 voltage-gated potassium channels regulate neurotransmitter release from mouse motor nerve terminals." European Journal of Neuroscience 20, no. 12 (December 2004): 3313–21. http://dx.doi.org/10.1111/j.1460-9568.2004.03730.x.

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Olsen, Timothy, Alberto Capurro, Nadia Pilati, Charles H. Large, and Martine Hamann. "Kv3 K+ currents contribute to spike-timing in dorsal cochlear nucleus principal cells." Neuropharmacology 133 (May 2018): 319–33. http://dx.doi.org/10.1016/j.neuropharm.2018.02.004.

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El-Hassar, Lynda, Lei Song, Winston J. T. Tan, Charles H. Large, Giuseppe Alvaro, Joseph Santos-Sacchi, and Leonard K. Kaczmarek. "Modulators of Kv3 Potassium Channels Rescue the Auditory Function of Fragile X Mice." Journal of Neuroscience 39, no. 24 (April 1, 2019): 4797–813. http://dx.doi.org/10.1523/jneurosci.0839-18.2019.

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Journal articles on the topic 'Kv3'

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