Stanimirovic D B, Ball R, Durkin J P
Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada.
Acta Neurochir Suppl. 1997;70:1-3. doi: 10.1007/978-3-7091-6837-0_1.
In this study we demonstrate the stimulation of both glutamate uptake and Na,K-ATPase activity in rat astrocyte cultures in response to a sublethal ischemic insult in vitro. To measure sodium pump activity and glutamate uptake, 3H-glutamate and 86Rb were simultaneously added to the cultures in the presence or absence of 2 mM ouabain. Na,K-ATPase activity was defined as ouabain-sensitive 86Rb uptake. Cell death was assessed by exclusion of the vital dye, calcein-AM from cells. Concomitant transient increases (2-3 fold above control levels) in both Na,K-ATPase and glutamate transporter activities were observed in astrocytes after 2-4 hours of ischemia. By contrast, 24 hours of ischemia caused a profound loss of both activities which paralleled significant cell death. The addition of 5 mM glucose to the cells after 4 hours of ischemia prevented the loss of sodium pump activity and glutamate uptake, and rescued astrocytes from the lethal effects of 24 hours of ischemia.
在本研究中，我们证明了在体外对大鼠星形胶质细胞培养物施加亚致死性缺血损伤后，谷氨酸摄取和钠钾ATP酶活性均受到刺激。为了测量钠泵活性和谷氨酸摄取，在存在或不存在2 mM哇巴因的情况下，将3H-谷氨酸和86Rb同时添加到培养物中。钠钾ATP酶活性定义为对哇巴因敏感的86Rb摄取。通过排除细胞中的活性染料钙黄绿素-AM来评估细胞死亡。缺血2-4小时后，在星形胶质细胞中观察到钠钾ATP酶和谷氨酸转运体活性同时出现短暂增加（比对照水平高2-3倍）。相比之下，24小时的缺血导致这两种活性的严重丧失，这与显著的细胞死亡平行。缺血4小时后向细胞中添加5 mM葡萄糖可防止钠泵活性和谷氨酸摄取的丧失，并使星形胶质细胞从24小时缺血的致死效应中恢复。
