Central nervous effects of CRF and angiotensin II on cardiac output in conscious rats.
Studies were performed to determine whether the central nervous system actions of corticotropin-releasing factor (CRF) and angiotensin II (ANG II) on systemic arterial pressure are mediated, in part, through changes in cardiac output (CO). Changes in CO after intracerebroventricular administration of ANG II and CRF were assessed in conscious unrestrained rats bearing pulsed Doppler flow probes on the ascending aorta. Intracerebroventricular injection of CRF (0.15 nmol) increased arterial pressure (15-20 mmHg), heart rate (70-100 beats/min), and CO (25-35%) without significantly affecting total peripheral resistance. Intracerebroventricular injection of ANG II (0.1 nmol) produced similar elevations of arterial pressure (15-20 mmHg). However, the ANG II-induced pressor response was attended by significant decreases in heart rate (20 beats/min) and CO (10-15%) and significant increases in total peripheral resistance (30-40%). The results of these studies demonstrate that CO, as assessed by pulsed Doppler flow probe methodology, may be influenced significantly and differentially by central nervous system administration of CRF and ANG II.
Overton
J M
JM
Department of Pharmacology, College of Medicine, University of Arizona, Tucson 85724.
Davis-Gorman
G
G
Fisher
L A
LA
D000804:Angiotensin II / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002302:Cardiac Output / Q000187:drug effects* / Q000502:physiology; D002490:Central Nervous System / Q000187:drug effects* / Q000502:physiology; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
D000804:Angiotensin II; D003346:Corticotropin-Releasing Hormone