Release of neurotransmitters and hormones: similar and totally different

The release of signalling molecules from a variety of cell types proceeds along very similar lines. In nerve endings neurotransmitter is stored in membrane bound containers, so called vesicles. It is released on arrival of a nerve impulse by the process of exocytosis, i. e. fusion of the vesicle with the cellular membrane. Release of hormones from gland cells follows a similar pattern. The underlying cellular mechanisms utilize the same molecular building blocks in both systems. Nevertheless, the regulation of both processes turns out to be very different on close inspection. Most of these differences may reside in the fact, that at nerve endings the most important players – vesicles and calcium specific ion channels – are linked together in a highly-regulated and specific fashion.