EVIDENCE FOR DOPAMINE AS AN INHIBITOR OF VASOPROTEIN RELEASE IN MAN

Abstract
The effect of dopamine on vasopressin release was studied by the infusion of L-dopa, a dopamine precursor that crosses the blood-brain barrier. L-Dopa suppressed resting vasopressin levels and inhibited the rise of vasopressin produced by head-up tilt. Carbidopa, a decarboxylase inhibitor that does not cross the blood-brain barrier, blocked the action of L-dopa. Dopamine apparently inhibits the release of vasopressin, either by an action at pituitary level or at the medium eminence of the hypothalamus.