1-S07-1
P/Q-タイプCa2+チャネル、リアノジン受容体、BKチャネルからなる2重Ca2+ナノドメインにより、バースト発火が調節される
Double-Nanodomain Coupling of P/Q-type Ca2+ Channels, Ryanodine Receptors, and BK Channels Controls the Generation of Burst Firing
〇入江 智彦
Tomohiko Irie
国立医薬品食品衛研・薬理
Div. Pharm., National Institute of Health Sciences
Action potentials clustered into high-frequency bursts play distinct roles in neural computations. However, little is known about ionic currents that control the duration and probability of these bursts. We found that, in cartwheel inhibitory interneurons of the dorsal cochlear nucleus, the likelihood of bursts and the interval between their spikelets were controlled by Ca2+ acting across two Ca2+ nanodomains, one between plasma membrane P/Q-type Ca2+ channels and endoplasmic reticulum (ER) ryanodine receptors, and another between ryanodine receptors and large conductance, voltage- and Ca2+-activated K+ (BK) channels. Each spike triggered Ca2+-induced Ca2+ release from the ER immediately beneath somatic, but not axonal or dendritic, plasma membrane. Moreover, immunolabeling demonstrated close apposition of ryanodine receptors and BK channels. Double-nanodomain coupling between somatic plasma membrane and hypolemmal ER cisterns provides a unique mechanism for rapid control of action potentials on the millisecond timescale.