Kugler P, Weeger T, Horváth E
Institute of Anatomy, University of Würzburg, Germany.
Neuroscience. 1995 Jan;64(1):173-82. doi: 10.1016/0306-4522(94)00358-c.
Applying quantitative microscopic histochemistry, the activity of the mitochondrial glutamate dehydrogenase which is localized in astrocytes was determined in the molecular layer of the dentate gyrus of the rat hippocampus. This hippocampal region contains the important terminations of the glutamatergic perforant path. For comparison, determinations of the mitochondrial succinate dehydrogenase were performed, which is localized preferentially in terminals and dendrites. Two age groups of animals were examined: young adults (three months old) and aged subjects (24 months old). Both age groups were divided into controls, and animals killed three, 21 and 90 days following unilateral electrolytic lesion of the entorhinal cortex. The post-lesional shrinkage of the terminal field of the perforant path, ipsilateral to the lesion side, was determined and considered in the evaluation of enzymatic data. Statistic analysis revealed that ipsilateral to the lesion side there was a significant decrease of glutamate and succinate dehydrogenase activities in the terminal field of the perforant path three, 21 and 90 days following lesion. It is reasonable to assume that the decrease of succinate dehydrogenase activity (50-60%) was caused by the loss of mitochondria localized in degenerating terminals, whereas the decrease of glutamate dehydrogenase activity (20-30%) was related to the decrease of glutamatergic transmission following lesion. In the terminal field of the perforant path contralateral to the lesion side both significant increases and decreases of enzyme activities were measured following lesion. From these results it is concluded that the hippocampus contralateral to the lesion side cannot be considered as an appropriate intraindividual control. The comparison between young and aged animals showed no differences in the demonstration of glutamate dehydrogenase and only restricted differences in the activity level of succinate dehydrogenase post-lesion. Therefore, it is reasonable to assume that the post-lesional reactivity of the enzymes studied was very similar in both age groups.
应用定量显微组织化学方法，测定了大鼠海马齿状回分子层中星形胶质细胞内线粒体谷氨酸脱氢酶的活性。该海马区域包含谷氨酸能穿通通路的重要终末。为作比较，还测定了线粒体琥珀酸脱氢酶的活性，该酶主要定位于终末和树突。研究了两个年龄组的动物：青年成年组（3个月龄）和老年组（24个月龄）。两个年龄组又都分为对照组，以及在内嗅皮质单侧电解损伤后3天、21天和90天处死的动物。在评估酶学数据时，测定并考虑了损伤侧同侧穿通通路终末野的损伤后萎缩情况。统计学分析显示，损伤后3天、21天和90天，损伤侧同侧穿通通路终末野中谷氨酸和琥珀酸脱氢酶的活性显著降低。可以合理推测，琥珀酸脱氢酶活性降低（50 - 60%）是由于退变终末中线粒体的丧失所致，而谷氨酸脱氢酶活性降低（20 - 30%）与损伤后谷氨酸能传递的减少有关。在损伤侧对侧的穿通通路终末野，损伤后酶活性既有显著升高也有显著降低。从这些结果可以得出结论，损伤侧对侧的海马不能被视为合适的个体内对照。青年和老年动物之间的比较显示，谷氨酸脱氢酶的表现没有差异，损伤后琥珀酸脱氢酶的活性水平只有有限的差异。因此，可以合理推测，所研究的酶在两个年龄组中的损伤后反应性非常相似。
