Abstract
An acute dynamic exercise provokes the translocation of β-adrenergic receptors (β-AR) from light vesicle fractions to sarcolemmal membranes in rat myocardium. However, 15min after an acute exercise the density of β-AR in both fractions returned to the pre-exercise level. The mean maximal activity of adenylate cyclase in response to isoproterenol roughly paralleled the redistribution of β-AR. The dose-response curves, however, were substantially shifted to the right with increase in EC50 for isoproterenol stimulation of adenylate cyclase. Thus, the sensitivity of sarcolemmal β-AR was found to be blunted 15min afterwards.
