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 nanodomains, one between plasma membrane P/Q 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 (CICR) 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. Spike bursts are high-frequency clusters of spikelets found in many CNS neurons. Irie and Trussell show that the generation and shape of bursts is controlled by extremely rapid calcium-induced calcium release from the ER acting on potassium channels across nanodomain distances.
|Original language||English (US)|
|State||Published - Nov 15 2017|
- calcium channel
- endoplasmic reticulum
- potassium channel
ASJC Scopus subject areas