title: Characterization of histamine receptors in tracheal smooth muscle of Mastomys natalensis.
abstract: The tracheal smooth muscle of Mastomys natalensis contracted with carbachol administration while histamine (H) caused concentration-dependent relaxation. The Specific H2-receptor agonists 4-methyl histamine, dimaprit, impromidine and a high concentration of 2-methyl histamine (H1-agonist) caused relaxation similar to H which was selectively blocked by cimetidine. Low concentrations (10(-5)-10(-4) mol/L) of 2-methyl histamine and of H (10(-8)-10(-7) mol/L) occasionally produced small contractions. Mepyramine (pyrilamine) blocked the contraction but did not modify the relaxant effect of H and its agonists. The results suggest a preponderance of histamine H2-inhibitory receptors in the trachea of this animal.
authors.forename: R
authors.initials: R
authors.lastname: Shukla
authors.forename: R C
authors.initials: RC
authors.lastname: Srimal
authors.forename: B N
authors.initials: BN
authors.lastname: Dhawan
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology*; D009115:Muridae; D009119:Muscle Contraction; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D011968:Receptors, Histamine / Q000502:physiology*; D014132:Trachea / Q000187:drug effects
chemical_list: D008761:Methylhistamines; D011968:Receptors, Histamine; C025566:4-methylhistamine; D002217:Carbachol; C026259:2-methylhistamine