title: Tracheal epithelium releases a vascular smooth muscle relaxant factor: demonstration by bioassay.
abstract: Acetylcholine caused no relaxation of a rubbed strip from rabbit aorta (RASR) which was precontracted with phenylephrine. When the same strip was taken into epithelium-intact guinea-pig trachea, acetylcholine produced a slow-developing relaxation which was antagonized by atropine but not by propranolol, indomethacin, theophylline or hydroquinone. RASR was not relaxed by acetylcholine when it was taken from epithelium-rubbed trachea. The results indicate that acetylcholine releases vascular smooth muscle relaxant factor from tracheal epithelium.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000502:physiology; D004848:Epithelium / Q000502:physiology; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009569:Nitric Oxide; D010656:Phenylephrine / Q000494:pharmacology; D011817:Rabbits; D014132:Trachea / Q000502:physiology*; D014665:Vasodilator Agents / Q000502:physiology
chemical_list: D014665:Vasodilator Agents; D010656:Phenylephrine; D009569:Nitric Oxide; D006632:Histamine; D000109:Acetylcholine