endothelium plays a key role in the control of vascular patency and tone. Thus,
the main objective of the study was to determine the role of endothelium and
its derived relaxation factors in mediating relaxation of rat thoracic aorta,
in response to sulfur dioxide (SO2) derivatives “1:3 M/M sodium
bisulfite (NaHSO3) and sodium sulfite (Na2SO3)”
using PowerLab tissue bath system. Endothelial denudation enhanced
relaxation responses of SO2 derivatives with an IC50 of
6.11 mM as compared to control rings with an IC50 of 6.21 mM, as
well as the maximum relaxation (Emax)
was increased from 62.026% ± 6.527% to 83.13% ± 14.755%. Furthermore, the
relaxation responses to SO2 derivatives in aortic rings were significantly
enhanced by indomethacin, clotrimazole and methylene blue with IC50’s
of 4.8 mM, 5.33 mM and 4.01 mM, and Emax were raised to 101.1% ± 6.537%, 66.92 ± 7.538 and 104.68 ± 3.575, respectively.
Meanwhile, L-NAME did not alter dose-dependent relaxation of SO2 derivatives in comparison to control aortic rings. The results of this study
had shown that endothelium denudation and blocking of endothelium
derived-relaxation factors enhanced vasodilator effect of SO2; this
may clarify the role of endothelium in the vasodilatory mechanism of SO2.
 Adams, D.J. and Hill, M.A. (2004) Potassium channels and membrane potential in the modulation of intracellular calcium in vascular endothelial cells. Journal of Cardiovascular Electrophysiology, 15, 13. http://dx.doi.org/10.1046/j.1540-8167.2004.03277.x
 Zhang, D. (2007) Hydroperoxide-induced oxidative stress in the arterial wall: Pharmacological characterization of the effects on arterial contractility. Academic Thesis, Eberhard Karls Universitat Tübingen.
 Nie, A. and Meng, Z. (2005) Study of the interaction of sulfur dioxide derivative with cardiac sodium channel. Biochimica et Biophysica Acta, 1718, 7. http://dx.doi.org/10.1016/j.bbamem.2005.09.020
 Meng, Z., Qin, G., Zhang, B. and Bai, J. (2004) DNA damaging effects of sulfur dioxide derivatives in cells from various organs of mice. Mutagenesis, 19, 4. http://dx.doi.org/10.1093/mutage/geh058
 Nie, A. and Meng, Z. (2007) Sulfur dioxide derivatives modulate Na/Ca exchange currents and cytosolic [Ca2+]i in rat myocytes. Biochemical and Biophysical Research Communications, 358, 6. http://dx.doi.org/10.1016/j.bbrc.2007.05.008
 Li, J. and Meng, Z. (2009) The role of sulfur dioxide as an endogenous gaseous vasoactive factor in synergy with nitric oxide. Nitric Oxide, 20, 166-174. http://dx.doi.org/10.1016/j.niox.2008.12.003
 Meng, Z., Li, Y. and Li, J. (2007) Vasodilatation of sulfur dioxide derivatives and signal transduction. Archives of Biochemistry and Biophysics, 467, 291-296. http://dx.doi.org/10.1016/j.abb.2007.08.028
 Du, X., Zhang, C., Jin, H., Du, J. and Tang, C. (2006) Vasorelaxant effect of sulfur dioxide derivatives on isolated aortic rings of rats and its mechanisms. Journal of Peking University, 38, 581-585.
 Du, Z., Zhou, Y. and Yang, P. (2007) Sulfur dioxide derivatives increase a hyperpolarization-activated inward current in dorsal root ganglion neurons. Toxicology, 239, 180-185. http://dx.doi.org/10.1016/j.tox.2007.07.005
 Nie, A. and Meng, Z. (2005) Sulfur dioxide derivative modulation of potassium channels in rat ventricular myocytes. Archives of Biochemistry and Biophysics, 442, 187-195. http://dx.doi.org/10.1016/j.abb.2005.08.004
 Zhang, Q. and Meng, Z. (2009) The vasodilator mecha- nism of sulfur dioxide on isolated aortic rings of rats: Involvement of the K+ and Ca2+ channels. European Jour- nal of Pharmacology, 602, 117-123. http://dx.doi.org/10.1016/j.ejphar.2008.11.030
 Aziz, N., Malik, H., Safur, R., Samra, B., Sidra, R. and Anwar, H. (2009) Antihypertensive, antioxidant, antidyslipidemic and endothelial modulating activities of a polyherbal formulation (POL-10). Vascular Pharmacology, 50, 8. http://dx.doi.org/10.1016/j.vph.2008.09.003
 Dong, H., Gareth, J., Denise, G., William, C. and Christopher, R. (1997) NO/PGI2-independent vasorelaxation and the cytochrome P450 pathway in rabbit carotid artery. British Journal of Pharmacology, 120, 695-701. http://dx.doi.org/10.1038/sj.bjp.0700945
 Motulsky, H. and Christopolous, A. (2003) GrdaphPad Prism: Fitting models to biological data using linear and non-linear regression; a practical guide to curve fitting. GraphPad Software, Inc.
 Liu, D., Jin, H., Tang, C. and Du, J. (2010) Sulfur dioxide: A novel gaseous signal in the regulation of cardiovascular functions. Mini-Reviews in Medicinal Chemistry, 10, 1039-1045. http://dx.doi.org/10.2174/1389557511009011039
 Meng, Z., Li, J., Zhang, Q., Bai, W., Yang, Z., Zhao, Y. and Wang, F. (2009) Vasodilator effect of gaseous sulfur dioxide and regulation of its level by Ach in rat vascular tissues. Inhalation Toxicology, 21, 1223-1228.