Siemkowicz E, Hansen A J
Stroke. 1981 Mar-Apr;12(2):236-40. doi: 10.1161/01.str.12.2.236.
Hyperglycemia severely impairs the outcome from cerebral ischemia. In order to sort out whether impaired brain ion homeostasis contributes extracellular "K+], [Ca++], and [H+] concentrations, [K+]e, [Ca++]e and [H+]e, of the brain cortex, as well as the EEG, were monitored during and after 10 minutes of complete cerebral ischemia in normo- and hyperglycemic rats. In both groups, the EEG-activity disappeared in 10-20 seconds of ischemia, at a time when [K+]e, [Ca++]e and [H+]e started to increase. After about 1.5 min, [K+]e showed an abrupt increase and [Ca++]e a steep decrease in the normoglycemic group. In the hyperglycemic group the same event took place after about 3 min of ischemia. pHe decreased to 6.6 and 6.1 in the normoglycemic and hyperglycemic group, respectively. Following the ischemic episode [K+]e reached pre-ischemic level after 4 min, [Ca++]e after 13 min, and [H+]e after 30 min in both groups. Recovery of the EEG, however, was clearly different in the 2 groups. EEG-activity reappeared later in the hyperglycemic group and showed after one hour a pattern of burst-suppression activity while the normoglycemic group showed asynchronous activity resembling the control pattern. It is concluded that high glucose content in brain prior to ischemia - and hence lower brain pH during ischemia - does not interfere with the return of normal extracellular ion composition after cerebral ischemia, whereas the return and pattern of EEG activity is severely affected.
高血糖会严重损害脑缺血的预后。为了弄清楚脑离子稳态受损是否会导致大脑皮层细胞外的“K⁺]、[Ca²⁺]和[H⁺]浓度，即[K⁺]e、[Ca²⁺]e和[H⁺]e发生变化，在正常血糖和高血糖大鼠完全脑缺血10分钟期间及之后，对其大脑皮层的[K⁺]e、[Ca²⁺]e和[H⁺]e以及脑电图进行了监测。在两组中，脑电图活动在缺血10 - 20秒时消失，此时[K⁺]e、[Ca²⁺]e和[H⁺]e开始升高。大约1.5分钟后，正常血糖组的[K⁺]e急剧升高，[Ca²⁺]e急剧下降。在高血糖组中，相同的情况在缺血约3分钟后发生。正常血糖组和高血糖组的pHe分别降至6.6和6.1。缺血发作后，两组的[K⁺]e在4分钟后恢复到缺血前水平，[Ca²⁺]e在13分钟后恢复，[H⁺]e在30分钟后恢复。然而，两组脑电图的恢复情况明显不同。高血糖组脑电图活动恢复较晚，1小时后呈现爆发抑制活动模式，而正常血糖组呈现类似于对照模式的异步活动。得出的结论是，缺血前大脑中的高葡萄糖含量——因此缺血期间较低的脑pH值——并不干扰脑缺血后细胞外离子组成恢复正常，而脑电图活动的恢复和模式受到严重影响。
