Role of central ANG II receptors in stress-induced cardiovascular and hyperthermic responses in rats.
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 nonselective 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 expression of the tachycardia and hyperthermia, as well as the pressor response, induced by immobilization stress.
Saiki
Y
Y
Department of Physiology, Yamaguchi University School of Medicine, Japan.
Watanabe
T
T
Tan
N
N
Matsuzaki
M
M
Nakamura
S
S
D000804:Angiotensin II / Q000378:metabolism*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism*; D004837:Epinephrine / Q000097:blood; D005334:Fever / Q000209:etiology*; D006339:Heart Rate; D007103:Immobilization; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011945:Receptors, Angiotensin / Q000502:physiology*; D013312:Stress, Physiological / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D013610:Tachycardia / Q000209:etiology*
D057911:Angiotensin Receptor Antagonists; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D009638:Norepinephrine; D004837:Epinephrine