THE INFLUENCE OF THE NITRIC OXIDE DONOR ON CARDIAC CONTRACTILE PROPERTIES EX VIVO AND IN VIVO
Nitric oxide donors induce relaxation of blood vessels in the systemic and pulmonary circuits, but their effect on the contractile properties of the myocardium is still unclear. In this study, the effects of stable nitric oxide donor, dinitrosyl iron complexes with ligand glutathione («oxacom»), on the contractile function of the heart were evaluated in vivo in the presence of hypotensive effect and ex vivo in the isolated rat heart. A bolus injection of oxacom (10 mg/kg) quickly reduced blood pressure, increased contractility indices and reduced myocardial relaxation rate constant. These changes gradually normalized within 20 min. In the isolated heart, oxacom (0.01-2.7 pM) increased coronary perfusion flow rate by 13-21 % under the conditions of constant perfusion pressure, but did not affect myocardial contractility and relaxability. The presence of cardiotropic effect in experiments in vivo was probably due to a higher initial dose of oxacom