Functional Roles of Kv1 Channels in Neocortical Pyramidal Neurons

Guan, Dongxu; Lee, Jonathan cf; Higgs, Matthew H.; Spain, William J.; Foehring, Robert C.

doi:10.1152/jn.00933.2006

Cited by 72 publications

(75 citation statements)

References 50 publications

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“…ScTx-sensitive current was studied in 56 cells. Some of the included Kv1 and Kv2 data from animals aged 4 -5 wk were taken from our previous work (Guan et al 2006(Guan et al , 2007a(Guan et al , 2007b. A-type currents were studied in the absence of extracellular Cd 2ϩ in an additional group of 80 cells.…”

Section: Resultsmentioning

confidence: 99%

“…Previously, we demonstrated isolation of putative Kv1-and Kv2-mediated currents from 4-to 5-wk-old rats with specific toxins (Guan et al 2006(Guan et al , 2007a(Guan et al , 2007b. We assume here that the sensitivities of specific potassium channels to the toxins do not change over the age range tested.…”

Section: Development Of Specific Current Componentsmentioning

confidence: 86%

“…We previously measured this run-down and noted that after a stable period of 3-5 min the current runs down. The current that runs down first has very slow activation kinetics compared with the putative Kv1 or Kv2 components (Guan et al 2006(Guan et al , 2007a. All of our data for percent block were obtained within the initial stable period for current amplitude.…”

Section: Current Isolationmentioning

confidence: 91%

“…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). However, Kv1-mediated currents contribute to spike threshold in mature pyramidal cells (Bekkers and Delaney 2001;Guan et al 2007a).…”

Section: Development Of Excitability and Firing Patternsmentioning

confidence: 98%

“…Repetitive firing behavior also changes with age Christophe et al 2005;Kasper et al 1994aKasper et al , 1994bLorenzon and Foehring 1993;Maravall et al 2004aMaravall et al , 2004bMcCormick and Prince 1987;Metherate and Aramkis 1999;Oswald and Reyes 2008;van Brederode et al 2000;Zhang 2004). In mature pyramidal neurons, voltage-gated K ϩ channels contribute to the filtering and integration of synaptic inputs, as well as shaping firing rates and pattern (Guan et al 2007a;Higgs and Spain 2009;Schwindt et al 1988). Developmental changes in these channels should therefore play significant roles in the maturation of pyramidal cell function.…”

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confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

Section: Development Of Specific Current Componentsmentioning

confidence: 86%

Section: Current Isolationmentioning

confidence: 91%