VASODILATOR EFFECT OF PITUITARY ADENYLATE-CYCLASE ACTIVATING POLYPEPTIDE (PACAP) ON FEMORAL BLOOD-FLOW IN DOGS

The effect of PACAP, a new VIP-like neuropeptide, on femoral arterial blood flow was studied in anesthetized beagle dogs. Intra-arterial inf usion of PACAP38, PACAP27, or VIP (0.25-25 pmol/kg) induced a dose-rel ated increase in femoral blood flow. The dose-response curve for PACAP 27 or PACAP38 was similar to that for VIP, but the response to PACAP38 at 25 pmol/kg was significantly less than the others. The vasodilator effect of PACAP38, however, lasted three to four times longer than th at of PACAP27 or VIP. Vascular effects of PACAP38 and PACAP38(COOH) di d not differ. PACAP(1-15), PACAP(10-20), PACAP(27-38), and PACAP(27-38 )NH2 had little effect on blood flow. Thus, PACAP38 and PACAP27 are po tent VIP-like vasodilators of the femoral arterial bed in dogs; PACAP3 8, but not PACAP27, differs from VIP in its prolonged vasodilator effe ct.