D-半乳糖拟衰老模型大鼠的神经递质受体机制

Mechanism of neurotransmitter receptor in D-galactose mimetic aging rats

目的:探讨神经递质受体在D-半乳糖拟衰老模型大鼠发生中的作用。方法:选取3月龄Wistar大鼠40只,随机分为对照组20只、D-半乳糖组20只,每组动物雌雄各半。同期选取18～36月龄雌性非洲爪蟾(购自中国科学院发育所)20只为自然衰老组。对照组大鼠每日于颈背部皮下注射生理盐水,D-半乳糖组每日颈背部皮下注射D-半乳糖50mg/(kg·d),两组给药体积均为10mL/kg,连续给药6周。采用Morris水迷宫方法检测每只大鼠到安全岛的平均时间。各组大鼠Morris迷宫测定后快速断头取全脑,提取RNA。采用显微注射法,将所提取的RNA注射于成熟的爪蟾卵母细胞中,采用电压钳位方法记录表达到非洲爪蟾卵母细胞膜上的神经递质受体通道电流。结果:①脑组织总RNA含量:D-半乳糖组、自然衰老组和正常对照组比较差异无显著性意义(650.1±51.7,632.0±45.1,640.5±49.3,P>0.05)。②Morris迷宫检测:D-半乳糖组和自然衰老组的潜伏期明显比正常对照组延长[(23.1±6.4)s,(20.7±6.8)s,(15.4±5.3)s,P<0.01]。③脑神经递质受体峰电流检测:D-半乳糖和自然衰老组的乙酰胆碱明显低于正常对照组[(106.0±23.9),(90.9±14.1),(138.0±29.0)nA,P<0.01];D-半乳糖和自然衰老组的5-羟色胺明显低于正常对照组[(113.6±29.6,91.4±14.2,172.5±23.5)nA,P<0.05)。结论:D-半乳糖拟衰老大鼠和老龄组大鼠脑功能的衰退与其脑神经递质受体功能障碍有关。

AIM： To investigate the role of neurotransmitter receptor in D-galaetose （D-gal） mimetic aging rats. METHODS： Sixty Wistar rats of either sex were randomly divided into control group （3 months old, n=20）, D-gal group （3 months old, n=20） and natural aging group （18 months old, n=20）. And one female African clawed frog of 18-36 months old were purchased from Institute of Genetics and Developmental Biology, Chinese Academy of Science. The rats of control group and D-gal group were treated with daily subcutaneous injection of 10 mL/kg saline and D-gal （50 mg/kg） in naps respectively, for successive 6 weeks. Morris water maze was applied to measure the mean time of reaching safety island of each rat. And then all the rats were executed to fetch the whole brain and extract RNA. The mature oocytes of clawed frog were injected with the extracted RNA by microinjection, and double electrode voltage clamps were used to detect activated peak currents of expressed neurotransmitter receptor channel. RESULTS： ①Total RNA content of brain tissues： There was insignificant difference among D-gal group, natural aging group and control group （650.1±51.7, 632.0±45.1,640.5±49.3, P 〉 0.05）.②Morris water maze detection： The rats of D-gal group and natural aging group appeared an obviously prolonged latent period, compared with control rats [（23.1±6.4） s, （20.7±6.8） s, （15.4±5.3） s, P 〈 0.01].③Peak currents of neurotransmitter receptor：. Acetylcholine （Ach） was obviously lower in D-gal group and natural aging group than in control group [（106.0±23.9）, （90.9±14.1）, （138.0±29.0） hA, P 〈 0.01]; And 5-serotonin was also obviously lower in D-gal group and natural aging group than in control group [（113.6±29.6）, （91.4±14.2）, （172.5±23.5）.nA, P 〈 0.05]. CONCLUSION： The decreased cerebral function is related with the functional impairment of neurotransmitter receptor in D-gal mimetic aging rats and natural aging rats.