title: Effect of some new Histamine H2-receptor antagonists on the guinea-pig papillary muscle.
abstract: Several histamine H2-receptor antagonists (cimetidine, ranitidine, oxmetadine and tiotidine) were tested for their activity on the papillary muscle of the guinea pig stimulated by histamine. All of the compounds exerted a competitive antagonism against histamine the order of potency being tiotidine greater than oxmetidine greater than ranitidine greater than cimetidine. Oxmetidine was the only drug which at high concentrations (10-6 M) decreased in maximum response of histamine probably because of non specific effects of the molecule already described in the literature. As it was expected, the H1-receptor antagonist, mepyramine, exerted a non-competitive antagonism.
mesh_terms: D000818:Animals; D002927:Cimetidine / Q000494:pharmacology / Q000031:analogs & derivatives; D005663:Furans / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006168:Guinea Pigs; D006633:Histamine Antagonists / Q000494:pharmacology*; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects*; D011899:Ranitidine; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D005663:Furans; D006146:Guanidines; D006633:Histamine Antagonists; D006635:Histamine H2 Antagonists; D013844:Thiazoles; D002927:Cimetidine; D011899:Ranitidine; C023990:tiotidine