P173: Coupled Nitroso-Sulfide Signalization Triggers Specific Vasoactive Effects in Intrarenal Arteries of Patients with Arterial Hypertension

Abstract

In normotensive conditions, it has been confirmed that S-nitrosothiols, as a source of NO, interact with hydrogen sulfide (H₂S) and create new substance/s with specific vasoactive effects. This interaction could represent new regulator pathway also in hypertension. The aim of the study was to investigate the vasoactive effects of H₂S, GSNO, and products of H₂S/GSNO interaction in lobar arteries isolated from kidney after nephrec-tomy of patients suffering from arterial hypertension.

Changes in isometric tension after pre-contraction were evaluated. Acetyl-choline- induced vasorelaxation was significantly reduced compared to the effect induced by exogenous NO donor, sodium nitroprusside, probably suggesting an endothelium dysfunction. While 1 µmol/l Na₂S had a minimal effect on the vascular tone, 20 µmol/l evoked a slight vasorelaxation. GSNO at 0.1 µmol/l induced vasorelaxation which was significantly smaller compared to the effect induced by 1µmol/l. The mixture of GSNO (0.1 µmol/l) and Na₂S (1 µmol/l) induced significantly higher vasorelaxation compared to GSNO (0.1 µmol/l) alone only in 5^th minute without the differences in the speed. On the other hand, the mixture prepared from higher concentrations of GSNO (1 µmol/l) and Na₂S (10 µmol/l) induced a significantly higher (in 1st, 2nd, 5th, 10th minute) and faster vasorelaxation compared to the effect induced by GSNO (1 µmol/l) alone.

In conditions of arterial hypertension H₂S in interaction with GSNO regulated a vasoconstrictor-increased arterial tone towards of more pronounced vaso-relaxation compared to GSNO alone. We confirmed for the first time that specific vasoactive effects of coupled nitroso-sulfide signalization were triggered also in human arterial tissue.