[The effect of adaptation to a physical load on the endothelium-mediated reactions of isolated vessels and NO production in rats].

Adaptation to exercise exerts a beneficial therapeutic and protective effect in several cardiovascular diseases many of which are characterized by disorders of endothelium-dependent vascular responses. To evaluate a possible role of functional condition of the endothelium in protective effects of adaptation to exercise we studied the effect of such adaptation on endothelium-dependent constrictor and dilator responses of the isolated rat aorta and on nitric oxide (NO) production in the organism. It was shown that adaptation to exercise (swimming) increased the suppression by the endothelium of constrictor responses to norepinephrine and potentiated the endothelium-dependent relaxation to acetylcholine. Furthermore adaptation to exercise considerably increased the NO production in the heart, liver, spleen, kidney and intestine as assayed by the method of electron paramagnetic resonance. We suggest that the adaptive increase in synthesis and accumulation of NO in the organism may underlie the protective effect of dosed physical training in diseases attended by disturbance of the functional condition of vascular endothelium.