N-甲基-D-天门冬氨酸受体及其调控的钙内流在大鼠感染性脑损伤中的变化

为探讨Ｎ－甲基－Ｄ－天门冬氨酸（ＮＭＤＡ）受体及其调控的钙内流在感染性脑损伤发病机制中的作用，采用Ｆｕｒａ－２／Ａｍ荧光法检测大鼠大脑皮质突触体内游离钙浓度（［Ｃａ＋＋］ｉ）。结果表明，注射百日咳杆菌组的［Ｃａ＋＋］ｉ较对照组显著增加（Ｐ均＜０．０１），并与注菌时间呈正相关关系（４小时ｖｓ０．５小时和２４小时ｖｓ４小时，Ｐ＜０．０５和＜０．０１）。ＮＭＤＡ受体的非竞争性拮抗剂ＭＫ－８０１预处理组（ＭＢＰ）的［Ｃａ＋＋］ｉ、脑含水量和伊文思蓝含量均较注菌组显著减少（Ｆ值分别为７２．２５、１６．８９、１４．３６，Ｐ＜０．０１和＜０．０５），并以２４小时［Ｃａ＋＋］ｉ减少最为明显（Ｐ＜０．０１）。提示ＮＭＤＡ受体调控的神经元内钙超载在感染性脑损伤、尤其在迟发性脑损伤的发病机制中起着重要作用。

A study on the effects and mechanism of N methyl D aspartate receptor and influx of calcium on the rat brain injury induced by bordetella pertussis

Free calcium concentration (Ca ]i) in synaptosomes of cerebral cortexes in rats pretreated with a noncompetitive calcium antagonist, MK 801, was measured by Fura 2/Am with fluorescence spectrophotometer to elucidate the effect of N methyl D aspartate (NMDA)receptor and influx of calcium on brain injury induced by bordetella pertussis (BP). The results showed that Ca ]i in BP group significantly increased as compared with the control group (C) and operated control group (OC), respectively ( P <0.01). The results showed a positive correlation between Ca ]i and course of BP injection (4h vs 0.5h and 24h vs 4h in BP group, P <0.05 and <0.01, respectively), and that Ca ]i, brain water content and Evans blue (EB) content in the rats pretreated with MK 801 (MBP) significantly decreased as compared with BP group (F=72.25, 16.89, 14.36, P <0.01 and <0.05, respectively) and that Ca ]i was the lowest in 24h group ( P <0.01). These findings suggest that NMDA receptor and calcium influx mediated by the receptor play an important role in pathogenesis of the brain injury caused by infection, especially, in the delayed brain injury.