Vasopressin affects adenylate cyclase activity in rat brain: a possible neuromodulator

The effect of vasopressin on adenylate cyclase activity was measured in the homogenates of selected rat brain regions. Adenylate cyclase activity in homogenate of the caudate nucleus did not change significantly with various concentrations of vasopressin. Furthermore, vasopressin did not reliably alter adenylate cyclase activity in various brain regions. Vasopressin in low concentrations significantly enhanced the activation of caudate adenylate cyclase activity by dopamine. This effect of vasopressin was dose dependent. Maximal enhancement by vasopressin occurred at 100 microM vasopressin. These results indicate that vasopressin may not have a direct effect on brain adenylate cyclase activity but appears to modulate the action of dopamine on brain adenylate cyclase.