Exercise reduces epicardial coronary artery wall stiffness: roles of cGMP and cAMP

Objective: Exercise enhances the dilation of the epicardial coronary arteries by vasodilator drugs and blood flow. Our goal was to determine whether coronary; artery elastic properties were affected by brief exercise training. Methods: Arterial pressure and left circumflex coronary artery diameter were measured in dugs. Venous bolus injections of acetylcholine 5 mu g.kg(-1) (AGH) and nitroglycerin 25 mu g.kg(-1) (NTG) or infusions of adenosine 0.5 mu M/kg/min (ADO) were given. Fifteen-second coronary artery occlusions were performed. Dogs exercised 2 h.d(-1) for 7 d at 10.9 km.h(-1). Experiments were repeated. Pressure and coronary radius data. were used to calculate vessel wall stress and incremental wall modulus, E-inc. Results: Baseline E-inc and radius were not changed by exercise, Before exercise E-inc increased similarly from baseline for all vasodilators. After exercise, the increase in E-inc with ADO was unchanged. However, the increase was attenuated during AGH, abolished with occlusion, and reversed with NTG despite enhanced dilation. Conclusion: Data suggest that Functional remodeling of epicardial arteries begins soon after starting exercise training, before changes in resting vessel diameter, is mediated by cGMP, and contributes to increased vascular dilation. Brief exercise training enhances the vasodilating capability and elastic properties of large coronary arteries.