Comparison of the action of cholecystokinin, carbachol and vasoactive intestinal peptide on receptor-activated formation of cyclic GMP and cyclic AMP in the striatum and the pancreas.

Sulphated cholecystokinin octapeptide (CCK-8S) and sodium nitroprusside (SNP) increased the formation of cyclic GMP in rat striatal slices with no effect on cyclic AMP. CCK-8S, SNP and carbachol increased the formation of cyclic GMP in guinea-pig pancreatic lobules, but had no effect on levels of cyclic AMP. Vasoactive intestinal peptide (VIP) significantly stimulated the formation of cyclic AMP in both striatal and pancreatic tissue without effect on levels of cyclic GMP in these tissues. In rat striatal slices carbachol significantly inhibited the VIP-stimulated increase in cyclic AMP.