Role of central ang ii-receptors in stress-induced cardiovascular
and hyperthermic responses in rats.
Saiki, Yukio, Tatsuo Watanabe, Nobusuke Tan, Masunori Matsuzaki &
Shoji Nakamura.
The Department of Physiology and Department of Internal Medicine,
Yamaguchi University School of Medicine, Ube, Yamaguchi 755,
Japan
APStracts 3:0270R, 1996.
The present study was carried out using a biotelemetry system to
investigate whether central angiotensin II (ANG II) is involved in
stress-induced cardiovascular and body-temperature responses in rats.
Intracerebroventricular injections of the non-selective ANG II
-receptor antagonist saralasin and of the ANG II AT1-receptor
antagonist losartan attenuated both the heart rate and pressor
responses to immobilization-stress in a dose-dependent manner. The
elevation of plasma norepinephrine and epinephrine induced by
immobilization-stress was also suppressed by central ANG II-receptor
blockade, suggesting a general attenuation of stress-induced
sympathetic nervous and adrenomedullary activity by central ANG II
-receptor blockade. The hyperthermia induced by immobilization-stress
was attenuated by central ANG II AT1-receptor blockade in a dose
-dependent manner. The effects of central saralasin on the blood
pressure response induced by immobilization-stress were greater in
Wistar-Kyoto rats than in spontaneously hypertensive rats. The
present results suggest that central ANG II AT1-receptors are
involved in the expression of the tachycardia?and hyperthermia, as
well as the pressor response, induced by immobilization-stress.
Received 9 November 1995; accepted in final form 20 June 1996.
APS Manuscript Number R700-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996