[HYDROGEN SULFIDE DONOR, NAHS, RECOVERS CONSTITUTIVE NO SYNTHESIS AND ENDOTHELIUM-DEPENDENT RELAXATION OF ISOLATED AORTA IN OLD RATS].

Abstract

The objective of this study was to show the effect of H₂S donor, NaHS on the endothelium-dependent vasorelaxation, free radical state and cNOS uncoupling in old rats. In the aorta of old rats a combined oxidative and nitrosative stress develops that leads to cNOS uncoupling and decreased constitutive synthesis of the NO. That biochemical changes correlate with lowering of the endothelium-dependent relaxation of aortic smooth muscles (7.5 ± 1.4%, compared with 64.9 ± 3.5% in adults). It was found that, due to the combined inhibition of oxidative and nitrosative stress, NaHS restores constitutive de novo synthesis of NO by restoring cNOS coupling. Additionally, NaHS improves endothelium-dependent vasorelaxation by increasing (by 6.5 times) Ach-induced relaxation of aortic smooth muscles.