Centrally induced cardiovascular and sympathetic responses to hydrocortisone in rats
Takahashi, H.; Takeda, K.; Ashizawa, H.; Inoue, A.; Yoneda, S.; Yoshimura, M.; Ijichi, H.
American Journal of Physiology 245(6): H1013-H1018
1983
ISSN/ISBN: 0002-9513 PMID: 6362433 Document Number: 214155
Central effects of hydrocortisone were investigated by injecting it intracerebroventricularly (icv) while recording blood pressure and heart rate in awake rats. Dose-dependent increases in both blood pressure and heart rate occurred following injections of hydrocortisone. Pretreatment by icv injections of the angiotensin II antagonist, [Sar1-Ile8]angiotensin II, completely abolished vasopressor responses to subsequent injections of hydrocortisone. When rats were later anesthetized with urethane to allow recording of abdominal sympathetic nerve activity, hydrocortisone produced vasocpressor responses accompanied by corresponding increases in sympathetic nerve firing, which were also abolished by central pretreatment with either [Sar1-Ile8]angiotensin II or angiotensin I converting-enzyme inhibitor, captopril. Centrally administered hydrocortisone evidently stimulates the brain renin-angiotensin system to produce vasopressor responses by increasing sympathetic nerve firing.