Kv3.4 subunits enhance the repolarizing efficiency of Kv3.1 channels in fast-spiking neurons.
Neurons with the capacity to discharge at high rates--'fast-spiking' (FS) neurons--are critical participants in central motor and sensory circuits. It is widely accepted that K+ channels with Kv3.1 or Kv3.2 subunits underlie fast, delayed-rectifier (DR) currents that endow neurons with this FS ability. Expression of these subunits in heterologous systems, however, yields channels that open at more depolarized potentials than do native Kv3 family channels, suggesting that they differ. One possibility is that native channels incorporate a subunit that modifies gating. Molecular, electrophysiological and pharmacological studies reported here suggest that a splice variant of the Kv3.4 subunit coassembles with Kv3.1 subunits in rat brain FS neurons. Coassembly enhances the spike repolarizing efficiency of the channels, thereby reducing spike duration and enabling higher repetitive spike rates. These results suggest that manipulation of K3.4 subunit expression could be a useful means of controlling the dynamic range of FS neurons.
Baranauskas
Gytis
G
Department of Physiology, Feinberg School of Medicine, 303 E. Chicago Ave., Northwestern University, Chicago, Illinois 60611, USA.
Tkatch
Tatiana
T
Nagata
Keiichi
K
Yeh
Jay Z
JZ
Surmeier
D James
DJ
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D017398:Alternative Splicing; D000818:Animals; D002460:Cell Line; D002469:Cell Separation; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D011485:Protein Binding / Q000502:physiology; D021122:Protein Subunits / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011930:Reaction Time / Q000502:physiology; D051670:Shaw Potassium Channels
C492014:Kcnc4 protein, rat; D009479:Neuropeptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D051670:Shaw Potassium Channels