Beta-adrenergic receptor adaptation after an acute exercise in rat myocardium.
An acute dynamic exercise provokes the translocation of beta-adrenergic receptors (beta-AR) from light vesicle fractions to sarcolemmal membranes in rat myocardium. However, 15 min after an acute exercise the density of beta-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 beta-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 beta-AR was found to be blunted 15 min afterwards.
Izawa
T
T
Laboratory for Exercise and Applied Physiology, Tokyo College of Pharmacy, Hachioji, Japan.
Komabayashi
T
T
Suda
K
K
Shinoda
S
S
Tsuboi
M
M
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D005082:Physical Exertion; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012508:Sarcolemma / Q000201:enzymology / Q000378:metabolism*
D011943:Receptors, Adrenergic, beta; D000262:Adenylyl Cyclases; D007545:Isoproterenol