University of Tehran Press Progress in Biological Sciences 1016-1058 6 1 2016 06 01 Vasodilatory effects of nitric oxide, hydrogen sulfide and sulfur dioxide in rats: Time-dependent interaction study 19 30 59004 10.22059/pbs.2016.59004 EN Abbas B.Q. Salihi Department of Biology, College of Science, Salahaddin University-Erbil Mudhir S. Shekha Department of Biology, College of Science, Salahaddin University-Erbil, Erbil, Kurdistan Region, Iraq Omar A.M. Al-Habib Department of Biology, Faculty of Science, University of Zakho, Duhok, Kurdistan region, Iraq Journal Article 2016 04 10 The vasodilator response of nitric oxide (NO), hydrogen sulfide (H<sub>2</sub>S) and sulfur dioxide (SO<sub>2</sub>) were studied to<br />determine the significance of the actions and interactions of these gasotransmitters for controlling aortic tone in rats. The isometric tension of five separate sets of experiments was recorded. Sodium nitroprusside (SNP; NO donor), sodium disulphide (Na<sub>2</sub>S; H<sub>2</sub>S donor), SO<sub>2</sub> derivatives and their paired combinations were added to phenylephrine (PE)-induced contraction during the peak value. Then maximal relaxation rate was calculated four times at 5 min intervals. Tetraethylammonium (TEA) and Glibenclamide (GLIB) were applied for investigating the molecular mechanism of the gasses. While, in a separate set of experiments, we used either L-Arginine (L-Arg), L-Cysteine (L-Cyst) or L-nitroarginine methyl ester (L-NAME) before applying gasotransmitters. Highest and prolonged relaxation rate were recorded when SNP was combined with SO<sub>2</sub>. The combination of Na<sub>2</sub>S and SO<sub>2</sub>-induced vasorelaxation was blocked by TEA and GLIB pretreatments. L-Cyst decreased relaxation compared to SNP and vice versa to SO<sub>2</sub> induced vasorelaxation. L-Arg markedly attenuated relaxation responses of Na<sub>2</sub>S and SO<sub>2</sub> derivatives. Also, L-NAME delayed relaxation compared to Na<sub>2</sub>S and SO<sub>2</sub>. These results suggest that exogenous paired combinations of H<sub>2</sub>S, NO and SO<sub>2</sub> will enhance and elongate the rate of aortic relaxation. Meanwhile, preincubation of aortic rings with precursors attenuate the dilatory effects of exogenous studied gases. Gasotransmitters nitric oxide Hydrogen Sulfide Sulfur Dioxide Vasotion https://pbiosci.ut.ac.ir/article_59004_b38fd7fc217b209189e8cc2a38865a7d.pdf