Kv2 channels form delayed-rectifier potassium channels in situ.
A non inactivating potassium current known as the delayed rectifier plays a major role in membrane repolarization during an action potential. Whereas several candidate genes exist that code for potassium current, the identities of the molecular isotypes that are responsible in situ for membrane repolarization remain unidentified. We report that Kv2 channels play a major role in action potential repolarization. Kv2 channel elimination resulted in a reduction of the density of noninactivating potassium current and a prolonged impulse duration. In contrast, suppression of noninactivating current carried by Kv1 channels was much less effective in increasing action potential durations. Thus, whereas different potassium channels encode sustained potassium current, their contributions to action potential repolarization vary and require direct examination in situ. Our results indicate that Kv2 subunits function as classic delayed-rectifier channels in vertebrate neurons.
Blaine
J T
JT
Department of Physiology and Biophysics, Medical Scientist Training Program, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D051668:Delayed Rectifier Potassium Channels; D004625:Embryo, Nonmammalian; D015870:Gene Expression; D049452:Green Fluorescent Proteins; D051662:Kv1.1 Potassium Channel; D008164:Luminescent Proteins / Q000235:genetics; D008845:Microinjections; D008959:Models, Neurological; D009154:Mutation; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger / Q000008:administration & dosage / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D051669:Shab Potassium Channels; D014981:Xenopus
D051668:Delayed Rectifier Potassium Channels; D008164:Luminescent Proteins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D051669:Shab Potassium Channels; D051662:Kv1.1 Potassium Channel; D049452:Green Fluorescent Proteins