Atriopeptin III does not alter cardiac performance in rats.
The effects of atriopeptin III (APIII) on systemic haemodynamics were examined in 12 anaesthetized rats. Five minutes following intravenous injection (i.v.) of 10 micrograms/kg APIII, cardiac output CO, measured by electromagnetic flowmetry, stroke volume and mean arterial pressure (MAP) decreased by 14, 13 and 8% (P less than 0.05), respectively, and total peripheral resistance (TPR) increased by 10% (P less than 0.05). Heart rate (HR) and left ventricular end-diastolic pressure (LVEDP) did not change. In order to examine cardiac performance, whole blood was infused into three groups of 12 rats each receiving either no injection, APIII (10 micrograms/kg i.v.) or APIII (10 micrograms/kg i.v.) plus a continuous infusion of phenylephrine to increase MAP to pre-injection levels. Cardiac performance curves did not differ among the three groups. These data indicate that the immediate decreases in MAP and CO produced in rats by a maximum natriuretic bolus dose of APIII were not mediated by a negative myocardial inotropic effect.
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D009320:Atrial Natriuretic Factor