Evidence for dopaminergic regulation of vasopressin release in the anephric rat.

Arginine vasopressin (AVP) release elicited by osmotic stimuli induces variable hypertensive responses. In normotensive anephric rats, a significantly greater blood pressure response was elicited by hypertonic saline than by mannitol infusion, and was further enhanced by previous dopaminergic receptor blockade. Plasma levels of AVP were significantly more elevated after saline than after mannitol despite more pronounced elevation of plasma osmolality in the latter animals, and were the highest in dopaminergically blocked animals. These findings indicate that dopamine exerts an inhibitory effect on the release of AVP.