偏二甲基肼急性中毒对大鼠脑组织γ-氨基丁酸和谷氨酸的影响

Acute toxic effects of 1, 1 dimethylhydrazine on GABA and Glu in the brain in rats

目的：从神经递质方面研究偏二甲基肼（ＵＤＭＨ）经非暴露式气管染毒急性中毒的生化机理。方法：Ｗｉｓｔａｒ大鼠分为正常对照组和低、中、高３个剂量组（染毒剂量分别为８０、１６０、２４０ｍｇ／ｋｇ），分３个染毒时相点即３０、６０、和９０ｍｉｎ，测定大鼠脑中γ－氨基丁酸（ＧＡＢＡ）、谷氨酸（Ｇｌｕ）含量和谷氨酸脱羧酶（ＧＡＤ）、γ－氨基丁酸转氨酶（ＧＡＢＡ－Ｔ）活性。结果：（１）各剂量组ＧＡＢＡ含量和ＧＡＤ活性明显低于对照组（Ｐ＜０．０１），且存在一定的量效和时效关系。（２）高剂量组ＧＡＢＡ－Ｔ活性低于对照组（Ｐ＜０．０５）。（３）中、高剂量组Ｇｌｕ含量明显高于对照组（Ｐ＜０．０１）。结论：ＵＤＭＨ引起中枢神经系统中毒症状主要是由于ＧＡＤ活性降低引起ＧＡＢＡ含量降低所致。可能还与Ｇｌｕ含量升高有关。

Objective: To study the biochemical mechanism of the acute intoxication by 1, 1 dimethylhydrazine (UDMH) through intratracheal infection from the angle of neurotransmitter. Methods: Adult male Wistar rats were randomized into four groups: 1) Normal control group (NCG); 2) Low dosage group (LDG, 80mg/kg); 3) Middle dosage group (MDG, 160mg/kg); 4) High dosage group (HDG, 240mg/kg). The contents of GABA and glu and the activities of GAD and GABA T were determined at the 30th, 60th and 90th min after the infection. Results: 1) The content of GABA and activity of GAD were significantly lower in LDG, MDG and HDG than in the control (P<0.01). These two indices were in dose effect and time effect manners. 2) The activity of GABA T was significantly lower in HDG than in the control (P<0.05). 3) The content of Glu was remarkably higher in MDG and HDG than in the control (P<0.01). Conclusion: UDMH induces intoxication of the central nervous system through decreasing the activity of GAD to result in the decrease of the content of GABA. It also might be due to the increase Glu content in the brain.