[Contracting and relaxing action of substance P on the airway muscles in the dog].
In anesthetized and artificially ventilated dogs, trachea and bronchi with low resting tone responded to i.v. bolus injection of the substance P with constriction in a dose-dependent manner. The constriction was partially abolished after cooling of cervical vagi or administration of atropine. If the resting tone had been elevated with continuous administration of 5-HT, the bolus injection of the substance P evoked dilation of the trachea and bronchi, which was augmented by atropine and diminished by propranolol. The constrictor response to the substance P seems to be due to the direct interaction of the peptide with specific receptor and an indirect action through activating of vagal pathways. Dilatory response seems to be entirely indirect and mediated through both beta-adrenergic and unknown non-vagal non-histaminergic mechanisms.
D000818:Animals; D001980:Bronchi; D004285:Dogs; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D013373:Substance P / Q000494:pharmacology*; D014132:Trachea
D013373:Substance P
Sokrashchaiushchee i rasslabliaiushchee deĭstvie veshchestva P na muskulaturu vozdukhonosnykh puteĭ sobaki.