title: The effects of antagonists of vasoactive intestinal peptide on nonadrenergic noncholinergic inhibitory responses in feline airways.
abstract: Relaxations of the feline intrapulmonary bronchus (IPB) induced by VIP or nonadrenergic noncholinergic (NANC) inhibitory nervous stimulation were unaffected by the VIP receptor antagonist [Ac-Tyr1,D-Phe2]-GRF (1-29) (30 microM). A second VIP antagonist, [pCl-D-Phe6,Leu17]-VIP (30 microM), also had no effect on NANC relaxation responses or IPB sensitivity to VIP. However, responses to three of the four highest VIP concentrations were inhibited by this antagonist. These results indicate that [Ac-Tyr1,D-Phe2]-GRF (1-29) and [pCl-D-Phe6,Leu17]-VIP are not effective competitive antagonists of VIP receptors in feline airways and, hence, have but limited applicability in determining the role of VIP in mediating airway NANC inhibitory responses in this tissue.
mesh_terms: D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001980:Bronchi / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D002415:Cats; D004558:Electric Stimulation; D013007:Growth Hormone-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D009638:Norepinephrine / Q000502:physiology; D017337:Sermorelin / Q000031:analogs & derivatives; D014660:Vasoactive Intestinal Peptide / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: C048507:vasoactive intestinal peptide, 4-chloro-Phe(6)-Leu(17)-; D014660:Vasoactive Intestinal Peptide; D017337:Sermorelin; D013007:Growth Hormone-Releasing Hormone; C045616:somatotropin releasing hormone (1-29)-amide, N-Ac-Tyr(1)-Phe(2)-; D000109:Acetylcholine; D009638:Norepinephrine