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Fig. 1. Schematic illustration for ion channels shaping intrinsic excitability of the cerebellar PCs. Among various ion channels, this review focused on the resurgent Na+ channel (NaV1.6), subthreshold-activated K+ channels (KV1.1, 1.2 and 1.6; KV1.4 and KV4, D-type and A-type K+ channel, respectively), suprathreshold-activated K+ channels (KV3 subfamily) and Ca2+-activated K+ channels (SK and BK channel). Action potential is initiated at the action potential initial segment (AIS) near the axon hillock and then passively propagated into the dendritic area. Somatic SK and BK channels determine the AP spike waveform such as the amplitude of afterhyperpolarization (AHP) and KV3 subfamily regulates repolarization of AP. Because the cerebellar PCs, in particular, are fast-spiking neurons, mechanisms of rapid recovery from NaV inactivation is required to stably maintain PC spiking behavior. NaV1.6 activity enables to rapidly fire the AP spikes via shortening refractory period. Various ion channels synergistically and dynamically modulate the dendrosomatic activity of the cerebellar PCs.
Exp Neurobiol 2018;27:139~154
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