Vasoactive intestinal polypeptide stimulation of cyclic AMP formation in rat central nervous system

Vasoactive intestinal polypeptide (VIP) stimulated cyclic AMP formation in the anterior pituitary, hypothalamus, pons and cerebral medulla of rat in vitro. The concentration of VIP above 10(-7) M significantly raised cyclic AMP level of these tissues with dose-dependency and the maximum stimulation of cyclic AMP formation was obtained at 5 min incubation. This stimulatory effect of VIP was not inhibited by propranolol or somatostatin. However, no enhancement of hormone release from the anterior pituitary or hypothalamus into the incubation medium by VIP was observed. These results suggest that VIP may act through adenylate cyclase in specific areas of rat central nervous system independent of beta-adrenergic receptor, but it may not necessarily be related to hormone release from the anterior pituitary or hypothalamus.