Neuronal Store-Operated Calcium Channels.

The endoplasmic reticulum (ER) is the major intracellular calcium (Ca 2+ ) storage compartment in eukaryotic cells. In most instances, the mobilization of Ca 2+ from this store is followed by a delayed and sustained uptake of Ca 2+ through Ca 2+ -permeable channels of the cell surface named store-operated Ca 2+ channels (SOCCs). This gives rise to a store-operated Ca 2+ entry (SOCE) that has been thoroughly investigated in electrically non-excitable cells where it is the principal regulated Ca 2+ entry pathway. The existence of this Ca 2+ route in neurons has long been a matter of debate. However, a growing body of experimental evidence indicates that the recruitment of Ca 2+ from neuronal ER Ca 2+ stores generates a SOCE. The present review summarizes the main studies supporting the presence of a depletion-dependent Ca 2+ entry in neurons. It also addresses the question of the molecular composition of neuronal SOCCs, their expression, pharmacological properties, as well as their physiological relevance.