There is certain evidence that high efficacy of beta-adrenoblockers with alpha-adrenoblocking effect (vasodilating beta-blockers) in
congestive heart failure (CHF) can be explained by their effect on
nitric oxide (NO) metabolism. In this context, the possible effects of
carvedilol and
proxodolol on the NO level in different organs have been studied on CHF model. The
heart failure was modeled in rats by
ligation of the coronary artery. Operated animals were divided into experimental groups treated with
carvedilol or
proxodolol and the untreated (control) group. In addition, a group of
sham-operated animals was formed. After 28 days of treatment, the NO level was measured in heart, liver, and kidneys using the EPR method with spin trap. It was found that, in
carvedilol-treated group, the NO level in liver is significantly lower than in other groups, which can be explained by the inhibitory action of
carvedilol on the NO metabolism in this organ. The NO levels in myocardium and kidney in the control group were higher than in the
sham-operated group, which confirms previous findings that the NO levels increases in CHF. Both drugs significantly decreased the NO concentration in myocardium and kidney tissue compared to control animals.