[Non-quantal mediator release: myth or reality?].

In the present review we analyze the papers devoted to phenomenon of non-quantal mediator release from the modern concepts of the functioning of synaptic contacts. In this connection the conception of quantal mediator release by itself is discussed as well as the mechanisms underlying the both the quantal and the non-quantal modes of signal molecules secretion. The data are systematized which verify the existence of the non-quantal mode of signaling in different synapses and demonstrate its physiological role.