Effects of tetrandrine on release of calcium-dependent endothelium-derived relaxant factor
Zheng, X.F.; Pan, H.W.; Bian, R.L.
Zhongguo Yao Li Xue Bao 8(6): 525-529
1987
ISSN/ISBN: 0253-9756 PMID: 3502520 Document Number: 297613
In calcium-free Krebs solution, the inhibition f endothelium-dependent relaxation induced by acetylcholine (ACh) in rabbit aortic rings was observed, but the inhibition was antagonized when Ca2+ was added. In KC1 40 mmol/L and phenylephrine (PE) 1 .mu.mol/L groups, the relaxations evoked by ACh in aortic rings were not inhibited by tetrandrine (Tet) < 30 .mu.mol/L and verapamil (Ver) < 10 .mu.mol/L, but were suppressed by Tet 30 .mu.mol/L and Ver 10 .mu.mol/L. It is concluded that the release of endothelium-derived relaxant factor (EDRF) induced by ACh is depended on extracellular calcium. The stimulated liberation of EDRF is inhibited by a large dose of Tet (30 .mu.mol/L) or Ver (10 .mu.mol/L). The results may indicate that the characteristics of calcium channel of endothelial cells are not identical with those of the smooth muscle cells.