Vasodilatation of sulfur dioxide derivatives and signal transduction

The vasodilatation of sulfur dioxide (SO2) derivatives on the rat thoracic aortic rings and its cell signal transduction pathway were studied. The levels of cAMP, cGMP, PGI2, TXA2 and activities of PKA and adenylyl cyclase (AC) in the rings exposed to SO2 derivatives were determined. The results indicated that SO2 derivatives could dose-dependently relax the isolated rat aorta rings with or without endothelium precontracted by NE, no difference was found between the rings with and without endothelium; Levels of cAMP, PGI2, AC activity and PKA activity in the aortic rings were significantly increased by the derivatives in a dose-related way; No change of cGMP and TXA2 levels in rings was observed; cAMP/cGMP and PGI2/TXA2 ratios were increased significantly by the SO2 derivatives. These results led to the conclusions that SO2 derivatives might cause the endothelium-independent vasorelaxation effect, and the vasorelaxation was mediated in partly by the signal transduction pathway of PGI2-AC-cAMP-PKA.