Despite the considerable progress in the understanding of the molecular mechanisms of neurosecretion achieved last years, many aspects of this problem remain unsolved. At present, release of neurotransmitter from the synaptic terminal (exocytosis) is considered as a complex multistep calcium-dependent process; the main steps of this process are "docking", i.e. close rapprochement of the synaptic vesicles with the cytoplasmic side of the membrane of the synaptic terminal, preparation of the vesicles for fusion, and fusion itself, the unification of the synaptic vesicle membranes and presynaptic membrane with pore formation, followed by mediator eflux to the synaptic cleft (Sollner et al., 1993; Sudhof, 1995). It is known that many proteins, membrane or cytoplasmic, are involved in all stages of the neurosecretory processes. Various enzymes, including protein kinases, phosphatases, phospholipases and proteinases.