Characterization of the receptor response for the neuropeptide Y-evoked suppression of parasympathetically-mediated contractions in the guinea pig trachea.
Neuropeptide Y (NPY) acts via several distinct receptor types. The aim of the present study was to examine which NPY receptors are coupled to inhibition of parasympathetically-mediated contractions of the isolated guinea pig trachea. Electrical field stimulation of tracheal rings evoked a rapid twitch, which was abolished by atropine (1 microM). NPY, the structurally related hormone peptide YY (PYY), the Y2 receptor agonist [Cys2, Aoc5-24, D-Cys27]NPY, as well as NPY 5-36 and NPY 13-36 evoked a concentration-dependent inhibition of the electrically-stimulated twitches. Pretreatment with the Y1 receptor-selective antagonist BIBP3226 (1 microM) failed to prevent the NPY-induced inhibition. Although less potent than NPY, the Y1 (and Y4-Y6) receptor agonist [Leu31, Pro34]NPY also inhibited the electrically-stimulated twitches. Another NPY-related peptide, pancreatic polypeptide, which recognizes Y4-Y6 receptors did not affect the stimulated twitches at concentrations up to 1 microM. However, pretreatment with the Y1 receptor-selective antagonist BIBP3226 (1 microM) virtually abolished the inhibition evoked by [Leu31, Pro34]NPY. None of the peptides affected the baseline tension and BIBP3226 (1 microM) per se did not affect the amplitude of the electrically-stimulated twitches. In conclusion, it seems that NPY and PYY are capable of suppressing parasympathetically mediated contractions in the guinea pig trachea mainly via Y2 receptors, but there is also a small contribution from Y1 receptors.
Grundemar
L
L
Department of Clinical Pharmacology, Lund University Hospital, Sweden. Lars.Grundemar@klinfarm.lu.se
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009478:Neuropeptide Y / Q000031:analogs & derivatives / Q000494:pharmacology*; D010191:Pancreatic Polypeptide / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D019894:Peptide YY / Q000494:pharmacology; D017476:Receptors, Neuropeptide Y / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism; D014132:Trachea / Q000294:innervation
C092926:BIBP 3226; D009478:Neuropeptide Y; D010446:Peptide Fragments; D017476:Receptors, Neuropeptide Y; C062924:neuropeptide Y (13-36); C095889:neuropeptide Y2 receptor; D019894:Peptide YY; C062259:neuropeptide Y, Leu(31)-Pro(34)-; D010191:Pancreatic Polypeptide; D001285:Atropine; D001120:Arginine