Exercise and beta-adrenergic regulation of rat cardiac myosin isoforms

摘要

Backgorund. The purpose of this experiment was to examine the effects of both exercise and β-adrenergic receptor blockade on the expression of native cardiac myoshin isoforms. Specifically, this experiment tested two hypotheses: 1) treatment of seden- tary rats with the beta blocker, propranolol, will promote increased ventricular V_3 (slow) native myosin content with a concomitant reduction of V_1 (fast) myosin isoforms; and 2) endurance exercise training will result in an increased sym- pathetic drive and therefore will retard the propranolol-induced shift in cardiac myosin isoform expression.