Evidence for a prostacyclin-mediated chronotropic effect of angiotensin II in the isolated cat right atria.
The positive chronotropic effect of angiotensin II was studied on the isolated spontaneously beating cat right atria. Angiotensin II and prostacyclin produced similar positive chronotropic and inotropic effects which were not affected by beta-adrenoceptor and histamine H2-receptor blockers. [Sar1,Ile8] angiotensin II, however, inhibited the positive chronotropic and inotropic responses to angiotensin II without altering that to prostacyclin, noradrenaline and histamine. Nicotine completely abolished the positive chronotropic action of angiontensin II without altering its positive inotropic effect. Nicotine failed to abolish the effects of prostacyclin, noradrenaline and histamine on the rate and contractility. These results were taken as evidence that the angiotensin II-induced increase in heart rate is probably mediated through the increase of prostacyclin biosynthesis in the isolated cat right atria.
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002415:Cats; D011464:Epoprostenol / Q000096:biosynthesis / Q000494:pharmacology*; D005260:Female; D006321:Heart / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D011453:Prostaglandins / Q000494:pharmacology*; D013268:Stimulation, Chemical
D011453:Prostaglandins; D000804:Angiotensin II; D006632:Histamine; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; D011464:Epoprostenol; D009638:Norepinephrine