Chronic [beta]-blockade reduces anti-adrenergic cardiac effects of
adenosine and carbachol by transregulation of inhibitory receptors
and giproteins.
Borst, Mathias M., Rainer Marquetant, Wolfgang K[umlaut]ubler, and
Ruth H. Strasser.
Department of Cardiology, University of Heidelberg, 69115
Heidelberg, Germany
APStracts 3:0533H, 1996.
Chronic blockade of stimulatory [beta]-adrenergic receptors may
decrease inhibitory receptors of the adenylyl cyclase signal
transduction sy stem. This transregulation process might reduce the
negative inotropic response of the myocardium to inhibitory receptor
stimulation. To test this, rats were treated for 6 days with the
[beta]-blocker atenolol (2 mg/d, i.p.). The density of [beta]
-adrenergic receptors in cardiac plasma membranes increased from 49+/
-6 to 75+/-9 fmol/mg protein (+/-SEM; p = 0.053), whereas muscarinic
M2 receptors significantly decreased (105+/-10 vs. 155+/-15 fmol/mg
protein; p
Received 29 January 1996; accepted in final form 6 November 1996.
APS Manuscript Number H83-6.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996