Neurosecretion (Regulated Exocytosis in Neuroendocrine Cells)

Neurosecretion is generally understood to mean release of peptides or amines from specialized neurons into the circulation. In mammals, the classical neurosecretory systems secrete oxytocin or vasopressin from axon terminals in the posterior pituitary and also peptides and amines controlling the anterior pituitary from terminals in the median eminence. Invertebrates have different systems not considered here, but with similar function. The peptides and amines are packaged in dense core vesicles which are released by exocytosis. The mechanism of exocytosis is similar to that in other cells and requires an increase in intracellular calcium. Neurosecretory neurons are known to exocytose dense core vesicles also from their dendrites. Dendritic secretion appears to be a general property of peptidergic neurons with widespread organizational roles in the central nervous system.