H₂receptor-mediated positive inotropic effect of histamine in neonatal guinea-pig left atria.
The receptor type mediating the positive inotropic effect of histamine was examined in left atria from neonatal guinea pigs. The positive inotropic effect of histamine, as well as its action potential prolonging effect, was antagonized by ranitidine, but not by chlorpheniramine or thiperamide. The positive inotropic effect was enhanced by isobutylmethylxantine. Receptor binding studies revealed the presence of both H₁ and H₂ receptor types. These results suggest that the positive inotropic effect of histamine in the neonatal guinea-pig atrium is mediated by H₂ receptors.
Department of Pharmacology, Toho University, Chiba, Japan.
Naoki
N
Agata
Yoshimitsu
Y
Kato
Iyuki
I
Namekata
Akira
A
Takahara
Hikaru
H
Tanaka
Daisuke
D
Chino
Katsuo
K
Koike
Yoshio
Y
Tanaka
D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D000831:Animals, Newborn; D002316:Cardiotonic Agents / Q000494:pharmacology*; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects* / Q000378:metabolism; D006632:Histamine / Q000494:pharmacology*; D017442:Histamine Agonists / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects*; D011969:Receptors, Histamine H1 / Q000378:metabolism*; D011970:Receptors, Histamine H2 / Q000378:metabolism*
D002316:Cardiotonic Agents; D017442:Histamine Agonists; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D006632:Histamine