Functional Role of the Fast Transient Outward K+CurrentIAin Pyramidal Neurons in (Rat) Primary Visual Cortex

Yuan, Weilong; Burkhalter, Andreas; Nerbonne, Jeanne M.

doi:10.1523/jneurosci.2858-05.2005

Cited by 84 publications

(126 citation statements)

References 40 publications

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“…However, in C. elegans, SHL-1 activates in a more depolarized voltage range than is typically observed for Shal channels in other species (37). Recent work has demonstrated that pyramidal neurons in the rat visual cortex also activate at more depolarized voltages than are typically observed in mammals (16). Nevertheless, SHK-1 currents operate in an even more depolarized voltage range and thus seem to maintain their relative functional relationship to SHL-1 channels, consistent with that found in other species (25, 38 -41, 53, 54).…”

Section: Discussionmentioning

confidence: 92%

“…Studies in cerebellar granule cells demonstrated a role for I A in determining the latency to first spike (13). I A has also been demonstrated to limit the back propagation of action potentials into the dendritic arbor (14), to impact long term potentiation in CA1 hippocampal neurons (15), to affect neuronal excitability in the visual cortex (16), and to modulate compartmentalization of membrane excitability in distal dendritic spines (17). Fast transient K ϩ currents in cardiac muscles contribute both to myocyte excitability (18) and to the fast repolarization phase of the cardiac action potential (2,8,19,20).…”

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confidence: 99%

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Mutant Analysis of the Shal (Kv4) Voltage-gated Fast Transient K+ Channel in Caenorhabditis elegans

Fawcett

Santi

Butler

et al. 2006

Journal of Biological Chemistry

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. We show that Shal channels also play a role as the predominant transient outward current in Caenorhabditis elegans muscle. Green fluorescent protein promoter experiments also revealed SHL-1 expression in a subset of neurons as well as in C. elegans body wall muscle and in male-specific diagonal muscles. The shl-1 (ok1168) null mutant removed all fast transient outward current from muscle cells. SHL-1 currents strongly resembled Shal currents in other species except that they were active in a more depolarized voltage range. We also determined that the remaining delayed-rectifier current in cultured myocytes was carried by the Shaker ortholog SHK-1. In shl-1 (ok1168) mutants there was a significant compensatory increase in the SHK-1 current. Male shl-1 (ok1168) animals exhibited reduced mating efficiency resulting from an apparent difficulty in locating the hermaphrodite vulva. SHL-1 channels are apparently important in fine-tuning complex behaviors, such as mating, that play a crucial role in the survival and propagation of the species.2 channels are key regulators of membrane excitability. Based on their inactivation kinetics, Kv currents can loosely be divided into two categories as follows: noninactivating or slowly inactivating K ϩ currents, and rapidly inactivating transient currents also known as "A-type" currents. A-type currents were first described in molluscan neurons by Hagiwara et al. (3) and later by Connor and Stevens (4), Neher (5), and Thompson (6). Classical A-type currents (I A ) are voltage-dependent, Ca 2ϩ -independent K ϩ currents that undergo rapid activation and inactivation. The classical A-type currents activate at subthreshold voltages and recover from inactivation quickly compared with other Kv currents. They are also characterized by strong steady-state voltagedependent inactivation. Repolarization to potentials negative to Ϫ50 mV is typically required to restore channel availability. A-type currents have a widespread distribution and are abundantly expressed in neurons and cardiac and smooth muscle cells, where they are thought to play many important physiological roles (2, 7-11).Connor and Stevens (12) proposed that the I A may determine the interspike interval in repetitively firing neurons. Studies in cerebellar granule cells demonstrated a role for I A in determining the latency to first spike (13). I A has also been demonstrated to limit the back propagation of action potentials into the dendritic arbor (14), to impact long term potentiation in CA1 hippocampal neurons (15), to affect neuronal excitability in the visual cortex (16), and to modulate compartmentalization of membrane excitability in distal dendritic spines (17). Fast transient K ϩ currents in cardiac muscles contribute both to myocyte excitability (18) and to the fast repolarization phase of the cardiac action potential (2,8,19,20). Finally, the pharmacological block of channels that carry fast transient currents in gastrointestinal smooth muscle in mice supports the conclusion that the window currents carried by ...

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Section: Discussionmentioning

confidence: 92%

mentioning

confidence: 99%

Mutant Analysis of the Shal (Kv4) Voltage-gated Fast Transient K+ Channel in Caenorhabditis elegans

Fawcett

Santi

Butler

et al. 2006

Journal of Biological Chemistry

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“…Because of its relatively hyperpolarized activation range and fast kinetics (Foehring and Surmeier 1993;Yuan et al 2005), the maturation of A-type current would be expected to lead to more rapid spike repolarization and narrower spikes. Lesser effects on spike parameters are expected for Kv1-mediated current (due to its small amplitude and slower kinetics; Bekkers and Delaney 2001; Guan et al 2006Guan et al , 2007a or Kv2-mediated currents (depolarized activation range and slow kinetics; Guan et al 2007b).…”

Section: Development Of Excitability and Firing Patternsmentioning

confidence: 99%

“…Several voltage-gated potassium channel (Kv) subunits and currents have been identified in the pyramidal neurons of juvenile rat cortex (Bekkers 2000a(Bekkers , 2000bGuan et al 2005Guan et al , 2006Guan et al , 2007bHamill et al 1991;Korngreen and Sakmann 2000;Nerbonne et al 2008;Norris and Nerbonne 2010;Yuan et al 2005), and developmental changes in action potential (AP) and firing properties suggest that Kv channel subunits may be developmentally regulated. To help understand the functional roles of specific current components and to facilitate comparisons between studies reporting K ϩ currents from animals of different ages, we systematically characterized the expression of the total potassium current and the relative contributions of putative Kv1-and Kv2-mediated current and A-type current during the first 5 wk of postnatal development of pyramidal cells from rat somatosensory cortex.…”

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confidence: 99%

Postnatal development of A-type and Kv1- and Kv2-mediated potassium channel currents in neocortical pyramidal neurons

Guan

Horton

Armstrong

et al. 2011

Journal of Neurophysiology

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Guan D, Horton LR, Armstrong WE, Foehring RC. Postnatal development of A-type and Kv1-and Kv2-mediated potassium channel currents in neocortical pyramidal neurons. J Neurophysiol 105: 2976-2988, 2011. First published March 30, 2011 doi:10.1152/jn.00758.2010.-Potassium channels regulate numerous aspects of neuronal excitability, and several voltage-gated K ϩ channel subunits have been identified in pyramidal neurons of rat neocortex. Previous studies have either considered the development of outward current as a whole or divided currents into transient, A-type and persistent, delayed rectifier components but did not differentiate between current components defined by ␣-subunit type. To facilitate comparisons of studies reporting K ϩ currents from animals of different ages and to understand the functional roles of specific current components, we characterized the postnatal development of identified Kv channel-mediated currents in pyramidal neurons from layers II/III from rat somatosensory cortex. Both the persistent/slowly inactivating and transient components of the total K ϩ current increased in density with postnatal age. We used specific pharmacological agents to test the relative contributions of putative Kv1-and Kv2-mediated currents (100 nM ␣-dendrotoxin and 600 nM stromatoxin, respectively). A combination of voltage protocol, pharmacology, and curve fitting was used to isolate the rapidly inactivating A-type current. We found that the density of all identified current components increased with postnatal age, approaching a plateau at 3-5 wk. We found no significant changes in the relative proportions or kinetics of any component between postnatal weeks 1 and 5, except that the activation time constant for A-type current was longer at 1 wk. The putative Kv2-mediated component was the largest at all ages. Immunocytochemistry indicated that protein expression for Kv4.2, Kv4.3, Kv1.4, and Kv2.1 increased between 1 wk and 4 -5 wk of age. Kv channel; somatosensory cortex; voltage clamp; A current; delayed rectifier AT BIRTH, the rodent somatosensory system is immature, and somatosensory cortex undergoes dramatic changes over the first postnatal month. Neocortical pyramidal cells are generated prenatally in an "inside-out" laminar pattern (Caviness 1982; Caviness et al.

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“…In many neurons, these properties impact repetitive firing rates (Connor and Stevens, 1971b;Kang et al, 2000;Kim et al, 2005;Yuan et al, 2005;Khaliq and Bean, 2008). In some cells, I A channels are active at subthreshold membrane potentials, influencing cell input resistances and excitability Yuan et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

IA Channels Encoded by Kv1.4 and Kv4.2 Regulate Neuronal Firing in the Suprachiasmatic Nucleus and Circadian Rhythms in Locomotor Activity

Granados‐Fuentes¹,

Norris²,

Carrasquillo³

et al. 2012

Journal of Neuroscience

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Neurons in the suprachiasmatic nucleus (SCN) display coordinated circadian changes in electrical activity that are critical for daily rhythms in physiology, metabolism, and behavior. SCN neurons depolarize spontaneously and fire repetitively during the day and hyperpolarize, drastically reducing firing rates, at night. To explore the hypothesis that rapidly activating and inactivating A-type (I A ) voltage-gated K ϩ (Kv) channels, which are also active at subthreshold membrane potentials, are critical regulators of the excitability of SCN neurons, we examined locomotor activity and SCN firing in mice lacking Kv1.4 (Kv1.4

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Functional Role of the Fast Transient Outward K⁺CurrentI_Ain Pyramidal Neurons in (Rat) Primary Visual Cortex

Cited by 84 publications

References 40 publications

Mutant Analysis of the Shal (Kv4) Voltage-gated Fast Transient K+ Channel in Caenorhabditis elegans

Mutant Analysis of the Shal (Kv4) Voltage-gated Fast Transient K+ Channel in Caenorhabditis elegans

Postnatal development of A-type and Kv1- and Kv2-mediated potassium channel currents in neocortical pyramidal neurons

IA Channels Encoded by Kv1.4 and Kv4.2 Regulate Neuronal Firing in the Suprachiasmatic Nucleus and Circadian Rhythms in Locomotor Activity

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