锰对大鼠纹状体谷氨酸代谢的影响

目的]观察锰对大鼠脑谷氨酸代谢的影响。方法]Wistar大鼠24只，按体重随机分成4组，每组6只。第1组为对照组，皮下注射0．9％氯化钠，第2～4组为锰染毒组，分别皮下注射8、40、200μmol／kg的氯化锰溶液，注射容量均为5mL／kg，染毒4周，每周5次。测定脑纹状体谷氨酰胺酶（PAG）、谷氨酰胺合成酶（GS）活性和谷氨酸（Glu）、谷氨酰胺（Gln）含量以及细胞凋亡率。结果]染锰4周后，随着染锰剂量的增加，PAG活性逐渐升高，而GS活性逐渐下降；同时Glu含量也逐渐升高，Gln含量逐渐下降；脑纹状体细胞凋亡率明显升高（P〈0．01）。结论]锰可以通过增强PAG活性和抑制GS活性，使Glu．Gln循环代谢紊乱，产生神经毒性。

Effect of Manganese on the Glutamate Metabolism in Rat's Striatum

Objective ] To observe the effect of manganese on the glutamate metabolism in rats striatum. Methods ] A total of 24 Wistar rats were divided into four groups by weight at random. The first group was the control group in which 0.9% NaCl was injected subcutaneously. The second to fourth groups were test groups in which 8, 40,200 μmol/kg MnCl2 respectively were injected subcutaneously with the capacity of each injection 5 mL/kg of body weight. 4 weeks after administration, the rats were sacrificed to get the tissue samples of their striatum. The activities of phosphate-activated glutaminase（ PAG ）, glutamine synthetase （ GS ）, the levels of glutamatic acid（ Glu ）, glutamine（ Gln ）and the ratio of apoptosis in rats striatum were determined. Results ] Compared with the control group, the PAG activity was increased and GS activity was decreased in the groups administered with Mn （ P 〈 0.01 ）. Moreover, Glu level was increased and Gln level was decreased in the group administered with Mn（ P 〈 0.01 ）. As the Mn dose injected increased, the ratio of apoptosis in rats striatum was also increased（ P 〈 0.01 ）. Conclusion ] Exposure to Mn in rats would influence the glutamate metabolism and induced apoptosis in rats striatum by activating PAG and restraining GS.