title: An evaluation of the efficacy of vasoactive intestinal polypeptide antagonists in vivo in the anaesthetized dog.
abstract: The effectiveness of competitive peptide vasoactive intestinal polypeptide (VIP) receptor antagonists was evaluated on heart rate in the anaesthetized dog. Two specific antagonists, VIP (6-28) and [D-p-Cl-Phe(6), Leu(17)]-VIP, and a nonspecific antagonist, pituitary adenylate cyclase activating peptide fragment (6-27) (PACAP), were studied. VIP (6-28) and [D-p-Cl-Phe(6), Leu(17)]-VIP (100 microg i.c.) increased the heart rate, whereas PACAP (100 microg i.c.) reduced the baseline heart rate. All three shifted the VIP dose-response curve to the right by two- to threefold for 30 min. In conclusion, PACAP, VIP (6-28), and [D-p-Cl-Phe(6), Leu(17)]-VIP have a direct effect on the heart rate, are equally effective, and the effects last approximately 30 min in vivo.
authors.affiliation: Department of Physiology, University College Cork, Ireland. hazim@ucc.ie
authors.forename: F
authors.initials: F
authors.lastname: Markos
authors.forename: B A
authors.initials: BA
authors.lastname: Hennessy
authors.forename: M
authors.initials: M
authors.lastname: Fitzpatrick
authors.forename: J
authors.initials: J
authors.lastname: O'Sullivan
authors.forename: H M
authors.initials: HM
authors.lastname: Snow
mesh_terms: D000818:Animals; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors*
chemical_list: D018005:Receptors, Vasoactive Intestinal Peptide