钙离子和抗氧化剂对毒黄素缩血管作用的影响

EFFECTS OF Ca2+AND ANTIOXIDANTS ON TOXOFLAVIN POTENTIATED VESOCONTRACTION ON ISOLATED RAT TAIL ARTERY

目的探讨毒黄素（Ｔｏｘｏｆｌａｖｉｎ，ＴＸＦ）增强大鼠离体尾动脉收缩力的作用机制。方法应用张力试验方法测定钙离子、抗氧化剂等在大鼠尾动脉对毒黄素作用的影响。结果ＴＸＦ的作用对细胞外钙有依赖性，并可被钙通道阻断剂硝苯吡啶所阻断。过氧化氢酶（Ｃａｔａｌａｓｅ，Ｃａｔ）和过氧化物歧化酶（ＳＯＤ）不影响ＴＸＦ对血管的作用，表明ＴＸＦ的作用不受氧自由基的影响。ＴＸＦ不影响咖啡因和Ｕ４６６１９引起的血管收缩。结论ＴＸＦ对平滑肌的作用可能是通过对钙通道的影响产生，这种影响取决于血管组织的收缩状态。

Objective The effect of TXF on the isometric contraction of rat tail artery stripes and the underlying mechanisms were investigated.Method To observe the effects of calcium and antioxidants on TXF potentiated Pheinduced vesocontraction.The tension development of rat tail arteries was measured.Result The vascular effect of TXF was not mediated by oxygenderived free radicals since catalase and SOD did not affect TXFenhanced vasocontraction.In contrast, the vasocontractor effect of TXF was dependent on extracelluar Ca2+ and abolished by nifedipine (a Ca2+antagonist).TXF had no effect on caffeine or U46619 induced vasocontraction.Conclusion TXF may potentially contract blood vessels via its effect on Ca2+ channels.This effect of TXF depends on the contractile status of the vascular tissues.