淀粉样β蛋白1-40对爪蟾卵母细胞表达的淋巴细胞神经递质受体功能的影响

观察淀粉样β蛋白_1-40(Aβ_1-40)对爪蟾卵母细胞表达的淋巴细胞神经递质受体(NR)功能的影响，探讨淋巴细胞NR功能检测在阿尔茨海默痴呆(AD)病理生理学上的意义. 将提取的人外周血淋巴细胞mRNA(50 ng)显微注射到成熟的非洲爪蟾卵母细胞，在(19.0±1.0)℃条件下孵育24 h后采用双电极电压钳位记录-60 mV维持电位时的受体激活电流. Aβ_1-40于记录前12 h加入孵育液. 结果发现注射人外周血淋巴细胞mRNA的爪蟾卵母细胞能表达出乙酰胆碱, 谷氨酸, 多巴胺, 5-羟色胺和γ-氨基丁酸受体. 这些表达的受体激活电流的共性是由氯离子载流的内向电流，其平衡电位接近于-22 mV. Aβ_1-40 60 nmol·L^-1对卵母细胞表达的NR功能有抑制效应，其NR峰电流降低分别为乙酰胆碱23%, 谷氨酸27%, 多巴胺25%，维生素E有拮抗Aβ_1-40效应的作用。外周血淋巴细胞NR功能检测作为AD外周评价指标值得更深入的研究.

Effects of amyloid β protein1-40 on the currents of expressed lymphocyte receptors in Xenopus oocytes

It is designed to investigate the effects of amyloid β protein(Aβ_1-40) on the functions of expressed lymphocyte neurotransmitter receptors(NRs) in Xenopus oocytes. Messenger RNA(mRNA) was prepared from peripheral lymphocytes of healthy adults and microinjected into maturated oocytes(stage Ⅴ-Ⅵ) with 50 nL (50 ng) for each oocyte. The microinjected oocytes were incubated with modified Bath′s solution for expression of receptor and their currents were recorded with double electrode voltage clamp technique. The results showed that oocytes expressed functional NRs originating from peripheral lymphocytes，which were similar to those from brain mRNA, including receptors of muscarinic acetylcholine (mACh), glutamate(Glu), dopamine(DA), serotonin(5-HT) and γ-aminobutyric acid(GABA). The current characteristics of these expressed receptors were inward currents carried by chloride ion with their equilibrium potentials close to -22 mV. Aβ_1-40 (60 nmol·L^-1 for 12 h) inhibited the peak currents of NRs by 23%(ACh), 27%(Glu) and 25%(DA), respectively. Vitamin E(0.1 mmol·L^-1) antagonized the inhibitory effect of Aβ_1-40.