[The neuropeptide PACAP: its presence, its mode of action and its receptors].

Specific PACAP type I receptors show 200- 1000-fold higher affinity for both PACAPS as compared to VIP. Their occupancy stimulates adenylate cyclase and frequently also the inositol phosphate-calcium cascade. Considering a few PACAP-38 and PACAP-27 effects exerted on the hypothalamo-hypophyseal axis and elsewhere, there appears already that these neuropeptides may play a physiological role even more important than that of VIP.