VPA解除Met对大鼠皮质神经元GAD表达的抑制

VPA解除Met对大鼠皮质神经元GAD表达的抑制

VPA解除Met对大鼠皮质神经元GAD表达的抑制 【摘要】 目的 研究丙戊酸(VPA)、蛋氨酸(Methionine，Met)对大鼠皮质神经元谷氨酸脱羧酶(GAD)表达的影响，探讨VPA对精神分裂症的治疗作用。方法 采用原代培养技术分组培养大鼠皮质神经元，收集细胞、制备GAD粗酶提取液，用比色法测定粗酶提取液GAD活力；分析空白组（无血清培养液）、Met组（无血清培养液含终浓度为2mM的Met培养3天后换以无血清培养液）、VPA组（无血清培养液含终浓度为2mM的Met培养3天后换以终浓度为0.5mM的VPA 无血清培养液）的GAD活性。结果 Met组GAD平均酶活力明显低于空白组，差异有统计学意义，而VPA组的GAD平均酶活力接近于空白组，差异无统计学意义。结论 蛋氨酸抑制大鼠皮质神经元表达GAD，降低GABA的合成；VPA促进皮质神经元表达GAD，可以使被Met抑制的GAD恢复到正常水平。

【关键词】 丙戊酸；蛋氨酸；谷氨酸脱羧酶；精神分裂症

Valproate renew GAD expression which had been inhibited by methionine in mouse primary cortical cultures

【Abstract】 Objective To study valproate and methionine(Met) regulate glutamic acid decarboxylase (GAD) expression in mouse primary cortical cultures nouron，investigate the mechanism of the VPA’s function in the treatment of schizophrenia.Methods Adopting primary cortical cultures technique cultures neuron，collecte cells，lysis cells，use colorimetric method to measure GAD activities；analyse GAD activities of the vacancy group（serum-free DMEM），the Met group（cultures were incubated with Met at a final concentration of 2 mM in serum-free DMEM for 3days，after that change it with serum-free DMEM），and the VPA group（cultures were incubated with VPA at a final concentration of 2 mM in DMEM after that incubated with Met at a final concentration of 2 mM in serum-free DMEM for 3days）.Results In the Met group the average activities of GAD is obviously lower than the other two group，the difference has statistical meaning. In the VPA group the average activities of GAD is approach to vacancy group，the difference hasn’t statistical meaning.Conclusion The methionine inhibits the cortical neuron express GAD，decreases GABA synthesize. The VPA promotes the cortical neuron expression GAD，and renews GAD expression which had been inhibited by Met in mouse primary cortical cultures.

【Key words】 valproate；methionine；glutamic acid decarboxylase（GAD）；schizophrenia

增加蛋氨酸（Methionine，Met）的摄入量，会造成近百分之七十的精神分裂症（schizophrenia，SZ）患者症状恶化［1］。有学者认为的大量摄入Met引起大鼠体内活性甲基供给体S-腺苷同型半胱氨酸（SAM）增加，SAM使谷氨酸脱羧酶(glutamic acid decarboxylase.GAD)等基因启动区甲基化修饰，引起GAD等基因表达降低［2］。在美国医生普遍使用丙戊酸(valproic acid，VPA）辅助治疗SZ。2001年Christopher［3］发现VPA能抑制组蛋白去乙酰基酶（Histone Deacetylase，HDACs)的活性，从而诱导基因表达。笔者通过原代培养技术培养大鼠皮质神经元，并在培养液中先后加入Met、VPA，然后用Berthelot［4］ 反应测定不同组别的皮质神经元裂解液的GAD相对酶活性。如果Met 能抑制GAD基因表达，将使皮质神经元中GAD的相对酶活性降低，而如果VPA能诱导GAD基因表达，将使GAD恢复到正常水平。