PRECONDITIONING WITH DOBUTAMINE IN THE ISOLATED RAT-HEART

The ability of dobutamine to precondition the isolated rat heart again st postischemic contractile dysfunction was assessed. Hearts were perf used with varying concentrations of dobutamine for 5 min followed by a 5 min ''washout'' period and 30 min of global ischemia. The hearts we re reperfused for 30 min to assess postischemic function. Dobutamine i mproved postischemic developed pressure, +dp/dt, heart rate x develope d pressure, end diastolic pressure, and coronary flow in a concentrati on-dependent manner. The concentration of dobutamine showing the maxim um protective effect was 10(-6)M. Propranolol administered with dobuta mine significantly attenuated the protective effect. The results indic ate that transient treatment with dobutamine can precondition the rat heart against ischemia/reperfusion injury. The mechanism of protection appears to involve beta-adrenergic stimulation.