[The hypotensive effect of nitrogen oxide obtained from exogenous and endogenous sources]

Correlation was studied between content of nitrogen oxide, developed in rat tissues after administration of nitroprusside, nitroglycerol or Fe(2+)-citrate, and the rate of these agents hypotensive effect. Content of nitrogen oxide in tissues was measured using EPR procedure by calculation of paramagnetic mononitrosyl ferrum complexes and exogenous ligand sodium diethyl thiocarbamate. After administration of nitroprusside these complexes developed only within several minutes when the drug exhibited hypotensive effect on animals as a result of nitrogen oxide production. The correlation was not found for nitroglycerol effect due to low level of nitrogen oxide obtained from this drug. Administration of Fe(2+)-citrate enabled to detect the mononitrosyl ferrum-ligand complexes in liver tissue within 1 hr after termination of these complexes hypotensive effect.