title: Atriopeptin III does not alter cardiac performance in rats.
abstract: 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.
mesh_terms: 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
chemical_list: D009320:Atrial Natriuretic Factor