Adenosine a1 receptors and its gene expression in ventricles from
spontaneously hypertensive rats..
Kobayashi, Shun-Ichi, Satoshi Umemura, Yoshiyuki Toya, Nobuhito
Hirawa, Shuuichi Hayashi, Kazuaki Uchino, and Masao Ishii.
Second Department of Internal Medicine, Yokohama City University,
School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236, Japan
APStracts 3:0107R, 1996.
We characterized the adenosine A1 receptor and the levels of its mRNA
expression in the ventricles of Wistar-Kyoto rats (WKY) and
spontaneously hypertensive rats (SHR) at the age of 6- and 13-weeks
-old. The binding of 2-chloro-[3H] cyclopentyladenosine ([3H]CCPA), an
A1 agonist ligand, to ventricular membranes was saturable and
reversible. The receptor density was significantly lower in SHR than
in WKY at 13 weeks. The Kd values were not different among these
groups. In Northern blot analysis using rat A1 receptor cDNA, levels
of mRNA did not differ significantly in the two groups at 13 weeks,
but the level in SHR significantly exceeded that in WKY rats in 6
weeks. Since plasma adenosine levels were reported to be increased at
13 weeks of SHR and we found mRNA levels were similar at this age,
the discrepancy between A1 receptor density and its mRNA levels might
be related to the desensitization of A1 receptors. Although the
implication of this decreased density of A1 receptor is not known, it
may involve in an increased susceptibility to ischemia.
Received 23 June 1994; accepted in final form 6 March 1996.
APS Manuscript Number R345-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96