Electron paramagnetic resonance study of nitric oxide production in rat heart during hypokinesia]

By the method of EPR spectroscopy we studied the intensity of nitric oxide (NO) production after modeling of hypokinesia in rats (limitation of moving activity) through analyses of the amount of NO-containing paramagnetic complexes in tissues of heart and liver. Experimental animals were kept during 60 day protracted hypokinesia. NO amount was assessed by the intensity of EPR spectra of complex (DEDTC)2-Fe(2+)-NO. It was established that after 60 day hypokinesia the 2-3 fold increase of NO quantity occured in heart and liver tissues. The application of a nonspecific inhibitor of NO-synthases, L-NAME, in suspended rats led to a decreased NO quantity up to the value more lower than in control. The obtained results show that the main contribution to the increase in the intensity of NO production during hypokinesia belongs to the fermentative pathway of NO production and the formation of NO by nitrite-reductase activity is not enhanced during hypokinesia.