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.