Vasopressin inhibits cyclic AMP accumulation and adenylate cyclase activity in cerebral preparations

Arginine-vasopressin (AVP) and lysine vasopressin (LVP) elicited a dose-dependent inhibition of noradrenaline-sensitive cyclic AMP accumulation in rat cerebral cortical slices, and of forskolin-stimulated adenylate cyclase activity in a rat cerebral cortical membrane preparation. In both cases LVP was more potent than AVP, and exerted half-maximal effects at concentrations similar to those found effective in binding studies on rat hippocampal membranes. In hippocampal slices, AVP did not affect cyclic AMP accumulation at low concentrations but potentiated the effect of noradrenaline at higher concentrations. In caudate membranes, AVP inhibited dopamine-stimulated adenylate cyclase with a similar dose-dependency to that seen for forskolin activation in cortex membranes.