title: Synergistic interaction between histamine and ouabain on ventricular fibrillation threshold.
abstract: The interaction between histamine and ouabain on the ventricular fibrillation threshold (VFT) was studied in the isolated, Langendorff-perfused heart of the guinea-pig. When administered separately, histamine and ouabain each reduced the VFT in a concentration-related manner with ED50 values of 84.3 and 250 nM, respectively. When perfused in combination the effects of these two drugs on VFT were significantly greater than the sum of their individual contributions. Mepyramine and cimetidine both antagonized the fibrillatory effects of the histamine-ouabain combination. Neither antagonist affected the fibrillation concentration-response curve for ouabain. These results suggest that both classes of histamine receptor may participate in the histamine-ouabain interaction.
authors.forename: J P
authors.initials: JP
authors.lastname: Trzeciakowski
mesh_terms: D000818:Animals; D002927:Cimetidine / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D004357:Drug Synergism; D004562:Electrocardiography; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology*; D011738:Pyrilamine / Q000494:pharmacology; D014693:Ventricular Fibrillation / Q000139:chemically induced*
chemical_list: D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D010042:Ouabain; D002927:Cimetidine; D006632:Histamine; D011738:Pyrilamine