Vasopressin, a nonapeptide, is synthesized in magnocellular neurons of
the paraventricular and supraoptic nuclei. Its release is stimulated
by increased osmolality, sensed by osmoreceptors in the lamina termina
lis, and by reductions in blood volume and blood pressure, sensed by a
rterial baroreceptors and cardiac receptors. The role of cardiac recep
tors is controversial.