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The effect of sodium nitroprusside, possible nitric oxide donor, on the activities of Ca2+, Mg(2+)- and Na+, K(+)-ATPases and lipid peroxidation was investigated in erythrocytes in vitro. Sodium nitroprusside caused 3-fold increase of mechanical and peroxidative erythrocyte hemolysis and also increase of bound malonic dialdehyde. Sodium nitroprusside-treated erythrocytes were also characterized by increased Na+, K(+)-ATPase activity.

The effect of neonatal sympathectomy on vasodilator responses to acetylcholine (ACh) and cAMP has been studied in aortic rings of spontaneously hypertensive rats (SHR) and normotensive animals. The relaxation of intact SHR aorta in response to ACh and cAMP was 20-35% lower than that of normotensive rats. Sympathectomy in normotensive rats did not affect the level of blood pressure and aorta reactivity to Ach. In SHR, sympathectomy caused a decrease in blood pressure, while relaxation in response to ACh and cAMP increased, as compared to intact SHR, but remained lower than in normotensive rats. The data obtained suggest that the decrease in arterial pressure of sympathectomized SHR is a result not only of the reduction in sympathetic effects but also of the increase in smooth muscle relaxation.