Action of pituitary adenylate cyclase-activating polypeptide and vasoactive intestinal polypeptide on the rat vascular system: effects on blood pressure and receptor binding

Abstract

The N-terminal fragment (PACAP 27) of the novel neuropeptide, pituitary adenylate cyclase-activating polypeptide 38 (PACAP 38), has 68% homology with vasoactive intestinal polypeptide (VIP). The administration of bolus doses of PACAP 38 and its 27 amino acid N-terminal fragment (PACAP 27) caused a rapid but transient dose-dependent hypotensive effect in the anaesthetized rat. The amplitude and duration of the response obtained by PACAP 38 was comparable with VIP whereas PACAP 27 was three times less potent than VIP. Furthermore, radioreceptor binding studies demonstrated that 125I-labelled PACAP 27 and 125I-labelled VIP bound to membranes prepared from blood vessels. Both PACAP 27 and VIP were capable of displacing the other from these binding sites. We propose that the hypotensive effect is via the same receptor type.

Comparative effects of PACAP and VIP on pancreatic endocrine secretions and vascular resistance in rat

“…It is well known that PACAP and VIP vasodilate various vascular beds but differences in their potency have been reported. Thus in rat, PACAP exhibited a similar potency to VIP in decreasing systemic arterial pressure (Nandha et al, 1991;Absood et al, 1992) and relaxing tail or mesenteric arteries (Absood et al, 1992;Huang et al, 1993). In contrast, PACAP has been reported to be 100 fold more potent than VIP in relaxing rabbit aorta (Warren et al, 1991).…”

The Neuropeptide Pituitary Adenylate Cyclase–Activating Polypeptide and Islet Function

“…PACAP is localized to nerves innervating blood vessels throughout the body (17,26). Furthermore, specific PACAP binding sites have been demonstrated on membranes isolated from blood vessels (58). PACAP also induces vasodilatation both in vitro and in vivo in different organs (49); for example, in healthy men PACAP potently induces vasodilatation in the brachial artery (59).…”

Evidence for a possible synergism between pituitary adenylate cyclase activating polypeptide and calcitonin gene‐related peptide in porcine ophthalmic artery

“…1991) and in vivo (Nandha et al 1991;Nilsson 1994) seems to be species dependent. PACAP-induced vasorelaxation in the porcine ophthalmic artery was sustained, an effect also seen in the rabbit aorta in vitro, and in vivo in the human forearm (Warren et al 1991(Warren et al , 1992.…”