自由基对细胞膜和Ach受体效应的损伤及枸杞多糖的防护作用

THE INJURY OF XENOPUS LAEVIS OOCYTES MEMBRANE AND ITS ACETYLCHOLINE RECEPTOR BY FREE RADICAL AND THE PROTECTION OF LYCIUM BARBARUM POLYSACCHARIDE

本研究将爪蟾卵母细胞暴露于黄嘌呤氧化酶－次黄嘌呤（ＸＯ－ＨＰＸ）反应系统，观察自由基对细胞膜及其乙酰胆碱（Ａｃｈ）受体的损伤，结果表明，在自由基的作用下膜被动电学参数发生显著变化，其效果与ＸＯ－ＨＰＸ的浓度和作用时间成正比，ＸＯ－ＨＰＸ作用２ｈ不影响膜功能，大于４ｈ各项膜功能指标明显下降，Ａｃｈ极化反应减弱，上升时间延长，去极化幅度下降，下降１／２时间缩短；超氧化物歧化酶（ＳＯＤ）可消除自由基对上述膜参数的影响。枸杞多糖可以使损伤膜的被动电学参数改善，但对Ａｃｈ去极化反应无恢复作用。结果提示，ＸＯ－ＨＰＸ反应系统是通过产生超氧阴离子自由基造成细胞膜和Ａｃｈ受体的损伤，枸杞多糖可对抗自由基对质膜的作用，但对Ｍ样受体无效。

The injury of the Xenopus laevis oocytes membrane and its acetylcholine receptor by free radicals was observed by exposing Xenopus laevis oocytes to the xanthine oxidase hypoxanthine(XO HPX) reaction system.The results showed that under the action of free radicals the passive electrical membrane parameters changed significantly,this effect was directly proportional to the concentration of XO HPX and the reaction time.The membrane function was not affected by 2 hours reaction with XO HPX,while significant decrease of various membrane functional indices was found after more than 4 hours reaction.the Ach polarization decreased,the rise time prolonged,the degree of depolarization decreased,the decay 1/2 time shortened.SOD may be used to eliminate the effect of free radicals on the above mentioned membrane parameters.Lycium barbarum polysaccharide(LBP)may be used to improve the passive electrical membrane parameters of the injured membrane,but it does not lead to the recovery of Ach depolarization. The results suggest that the injury of cell membrane and Ach receptor by XO HPX reaction system may be caused by the production of O - .2 free radicals. LBP may antagonize the action of free radicals on the membrane while it is ineffective in muscarine receptor injury.