Selective impairment of atrioventricular conduction by 2-(2-pyridyl)-ethylamine and 2-(2-thiazolyl)-ethylamine, two histamine H1-receptor agonists.
To further characterize the receptor mediating histamine-induced impairment of atrioventricular conduction, the effects of two selective histamine H1-receptor agonists, 2-(2-pyridyl)-ethylamine (PEA) and 2-(2-thiazolyl)-ethylamine (ThEA), were investigated using the isolated guinea pig heart. These effects were compared with those of histamine and other selective agonists. PEA and ThEA produced a weak stimulation of cardiac rate and contractility; however, they produced a marked prolongation of atrioventricular conduction. The orders of relative potencies observed substantiate the hypothesis that H2-receptors mediate the positive inotropic and chronotropic effects and H1-receptors mediate the negative dromotropic effect of histamine.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D005021:Ethylamines / Q000494:pharmacology*; D006168:Guinea Pigs; D006329:Heart Conduction System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D011968:Receptors, Histamine / Q000187:drug effects*; D011969:Receptors, Histamine H1 / Q000187:drug effects*; D013844:Thiazoles / Q000494:pharmacology
D005021:Ethylamines; D008761:Methylhistamines; D011725:Pyridines; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D013844:Thiazoles; D006632:Histamine