Epithelium-dependent relaxation of guinea-pig tracheal smooth muscle by histamine: evidence for non-H1- and non-H2-histamine receptors.
Epithelium-dependent modulation of the effect of histamine on airway smooth muscle of guinea-pig was studied by using the coaxial bioassay system. Histamine-induced contraction was followed by epithelium-dependent relaxation in the presence of indomethacin, propranolol, atropine and cimetidine. Mepyramine failed to prevent histamine-induced epithelium-dependent relaxation of carbachol-precontracted tracheal smooth muscle in the presence of cimetidine. This relaxant response could be prevented by an H3-histamine receptor antagonist, thioperamide. An agonist, (R) alpha-methylhistamine, of novel (H3)-histamine receptors was found ineffective to produce epithelium-dependent relaxation. It is concluded that the stimulation of non-H1- and non-H2-histamine receptors of guinea-pig airway epithelial cell layer takes part in the release of (a) relaxant factor(s), which counteracts, H1-histamine receptor-mediated bronchoconstriction.
Guc
M O
MO
Hacettepe University, Faculty of Medicine, Department of Pharmacology, Ankara, Turkey.
Ilhan
M
M
Kayaalp
S O
SO
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D004848:Epithelium / Q000502:physiology*; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011968:Receptors, Histamine / Q000187:drug effects*; D013997:Time Factors; D014132:Trachea / Q000187:drug effects
D011968:Receptors, Histamine; D006632:Histamine; D002217:Carbachol