title: Relative potencies of histamine H1-agonists on guinea-pig tracheal smooth muscle.
abstract: The relative potencies of a series of histamine H1-agonists in causing contraction of spirally cut strips of guinea-pig trachea, measured in the presence of cimetidine, indomethacin, methylatropine and propranolol, were similar to those reported on other guinea-pig tissues. However, whereas 2-methylhistamine and N alpha,N alpha-dimethylhistamine are apparently partial agonists in potentiating the adenosine-stimulated accumulation of cyclic AMP in slices of guinea-pig cerebral cortex, on tracheal spirals they are full agonists producing the same maximum contraction as histamine.
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011968:Receptors, Histamine / Q000187:drug effects*; D011969:Receptors, Histamine H1 / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects
chemical_list: D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D000242:Cyclic AMP