[The injury of Xenopus laevis oocytes membrane and its acetylcholine receptor by free radical and the protection of lycium barbarum polysaccharide].

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 O2- free radicals. LBP may antagonize the action of free radicals on the membrane while it is ineffective in muscarine receptor injury.