老年大鼠视皮层γ-氨基丁酸的代谢变化

目的 研究衰老过程中视皮层γ-氨基丁酸（GABA）的代谢变化及其性别差异。方法 采用纸电泳法检测青年大鼠和老年大鼠视皮层中GABA含量,采用比色法测定GAD与GABA-T活性。结果 老年大鼠较青年大鼠视皮层GABA含量显著下降,GAD活性明显降低,GABA-T活性老年雄性组显著上升,老年雌性组变化不显著。老年雌性组GABA含量明显高于老年雄性组,两组间GAD活性无显著差异,GABA-T活性老年雄性组较高。结论 老年大鼠视皮层GABA含量明显下降,可能与GAD活性的下降及GABA-T活性的上升有关,此外老年雌性GABA含量明显高于老年雄性,这可能是由于老年雄性GABA-T活性较高所导致的。

Changes of gamma-aminobutyric acid (GABA) metabolism in the visual cortex of aged rats

Objective To confirm and discuss gamma-aminobutyric acid(GABA) hypothesis of age-related visual function degradation by exploring changes of GABA metabolism in the visual cortex of the aged rats and its difference in gender through the measurement of GABA quantity,glutamic acid decarboxylase(GAD) and GABA-transaminase(GABA-T) activity.Methods The GABA content were detected by paper electrophoresis and the activity of GAD and GABA-T were measured by colorimetry in every experimental group.Results GABA content and activity of GAD in the aged group were significantly lower than those in the young rats.The activity of GABA-T were remarkably increased in the aged male group but remained constant in the aged female group.The GABA content was higher in aged female group than that in aged male group.There was no significant difference in GAD activity between the aged male and female groups.The GABA-T activity in aged male group was obviously higher than that in aged female group.Conclusions The decreased GABA content in the visual cortex of aged rats may be induced by the decrease of GAD activity and the change of GABA-T activity in aged rats.In addition,GABA content is higher in aged male group than that in aged female group,which might contribute to a higher GABA-T activity in aged male group.