title: Comparative study of vascular relaxation and receptor binding by PACAP and VIP.
abstract: The pharmacological properties of the pituitary adenylate cyclase activating peptides (PACAPs) and vasoactive intestinal peptide (VIP) were compared using: (i) relaxation of vascular and gastric smooth muscle in vitro, and (ii) radioligand binding to membrane preparations of a variety of tissues. Vasoactive intestinal peptide and PACAP-27 were similarly potent in relaxing rat mesenteric arteries, porcine coronary arteries, and rat gastric smooth muscle, whereas PACAP-38 was either more or less potent than the other two peptides depending on the tissue model. Cross-desensitization to relaxation and radioligand binding studies of porcine coronary arteries suggested that VIP and the PACAPs interact with a common receptor in this tissue. A PACAP-preferring receptor with low affinity for VIP was identified in radioligand binding studies of rat brain and anterior pituitary. A second, nonselective, receptor that binds VIP and both PACAPs with high affinity was observed in preparations of rat and porcine arteries and rat lung, liver, brain, and anterior pituitary.
authors.affiliation: Department of Medicine, University of Calgary, Alberta, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Huang
authors.forename: H
authors.initials: H
authors.lastname: Shirahase
authors.forename: O P
authors.initials: OP
authors.lastname: Rorstad
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009479:Neuropeptides / Q000378:metabolism / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D018005:Receptors, Vasoactive Intestinal Peptide / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000378:metabolism / Q000494:pharmacology*
chemical_list: C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018005:Receptors, Vasoactive Intestinal Peptide; D014665:Vasodilator Agents; D014660:Vasoactive Intestinal Peptide