Outside and in: development of neuronal excitability

Investigation of the development of excitability has revealed that cells are often specialized at early stages to generate Ca 2+ transients. Studies of excitability have converged on the central role of Ca 2+ and K + channels in the plasmalemma that regulate Ca 2+ influx and have identified critical functions for receptor-activated channels in the endoplasmic reticulum that allow efflux of Ca 2+ from intracellular stores. The parallels between excitability in these two locations motivate future work, because comparison of their properties identifies shared attributes. Ion channels are expressed on the neuronal cell membrane in a precise, time-dependent and coordinated fashion during development. Together, they interact to produce ionic fluxes that influence the differentiation and regulation of other channels.