This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tseng, C. J. Articles by Kuan, C. J. Search for Related Content PubMed PubMed Citation Articles by Tseng, C. J. Articles by Kuan, C. J.

Hypertension, Vol 24, 714-718, Copyright © 1994 by American Heart Association

ARTICLES

Modulatory effects of endogenous adenosine on epinephrine secretion from the adrenal medulla of the rat

CJ Tseng, WY Ho, HC Lin, CS Tung and CJ Kuan
Department of Pharmacology, National Defense Medical Center, Taipei, Taiwan, Republic of China.

The purpose of this study was to examine (1) whether endogenous adenosine receptors inhibit the release of epinephrine and norepinephrine from adrenal medulla in response to physiological and pharmacological stimuli and (2) whether the renin-angiotensin system modulates this effect of endogenous adenosine. We used a conscious animal model to approximate normal physiological conditions. Male Sprague-Dawley rats were treated with a surface adenosine receptor antagonist, 1,3-dipropyl- 8-(p-sulfophenyl)xanthine (DPSPX) to explore the effect of endogenous adenosine. Plasma epinephrine and norepinephrine levels in response to hydralazine-induced hypotension were measured in these animals. The same protocol was repeated in rats pretreated with either adrenalectomy or captopril. The results showed that DPSPX treatment significantly increased plasma epinephrine and norepinephrine levels at both baseline conditions and after hydralazine- induced hypotension. The results from the adrenalectomized rats showed that the difference in plasma epinephrine level between the control and DPSPX groups originated from the adrenal medulla. Pretreatment with captopril attenuated the rise of plasma epinephrine and norepinephrine levels in DPSPX-treated animals. This result suggests that endogenous adenosine receptors inhibit epinephrine release from the adrenal medulla and suppress plasma norepinephrine levels. When catecholamine release was stimulated by physiological and pharmacological stimuli, this inhibitory function of adenosine receptors was augmented. The renin-angiotensin system is at least partially responsible for the modulatory function of endogenous adenosine on the catecholamine response as demonstrated in this study.

This article has been cited by other articles:

				J. W. Daniels, P. A. Mole, J. D. Shaffrath, and C. L. Stebbins Effects of caffeine on blood pressure, heart rate, and forearm blood flow during dynamic leg exercise J Appl Physiol, July 1, 1998; 85(1): 154 - 159. [Abstract] [Full Text] [PDF]