DYNAMICS OF INTERSTITIAL AND INTRACELLULAR PH IN EVOLVING BRAIN INFARCT
DYNAMICS OF INTERSTITIAL AND INTRACELLULAR PH IN EVOLVING BRAIN INFARCT
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DOI：
10.1152/ajpregu.1991.260.3.r581
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发表时间：
1991-03-01
影响因子：
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通讯作者：
PULSINELLI, WA
中科院分区：
文献类型：
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作者：
NEDERGAARD, M;KRAIG, RP;PULSINELLI, WA
我们在大鼠局灶性缺血模型中研究了细胞内pH（PH（i））和间质pH（pH（e））之间的关系。 在右侧大脑中动脉和颈总动脉（MCA-CCAO）闭塞的大鼠中，用pH敏感微电极测量间质pH，并用[C-14]二甲双酮法测量平均组织pH。 在正常皮质中，pH（e）和pH（i）分别为7.24 +/- 0.07和7.01 +/- 0.13（平均值+/- SD，n = 6）。 在缺血皮质中，MCA-CCAO后1 h，pH（e）降至6.43 +/- 0.13，而pH（i）仅降至6.86 +/- 0.11（n = 5）。 缺血4小时后，pH（e）为6.61 +/- 0.09，pH（i）为6.62 +/- 0.20（n = 4）。 在缺血前用葡萄糖处理显著降低了缺血后1小时测量的pH（e）（5.88 +/- 0.17），但没有降低pH（i）（6.83 +/- 0.03，n = 4）。 在用胰岛素预处理的低血糖动物的缺血皮质中，pH（e）（7.25 +/- 0.06）和pH（i）（6.99 +/- 0.13，n = 4）均未降低。 pH（i）和pH（e）的差异表明，一些细胞保持足够的功能以维持进展中的梗死内质子的质膜梯度。 如果计算的pH（i）值准确地反映了严重局灶性缺血区域内细胞的真实pH（i），则脑梗死可以在与正常相比没有显著改变的pH（i）水平下进行。
We examined the relationships between intracellular pH (PH(i)) and interstitial pH (pH(e)) in a rat model of focal ischemia. Interstitial pH was measured with pH-sensitive microelectrodes, and the average tissue pH was measured with the [C-14]dimethadione method in rats subjected to occlusion of the right middle cerebral and common carotid arteries (MCA-CCAO). In normal cortex, pH(e) and pH(i) were 7.24 +/- 0.07 and 7.01 +/- 0.13 (means +/- SD, n = 6), respectively. In the ischemic cortex, pH(e) fell to 6.43 +/- 0.13, whereas pH(i) decreased only to 6.86 +/- 0.11 (n = 5) 1 h after MCA-CCAO. After 4 h of ischemia, the pH(e) was 6.61 +/- 0.09 and pH(i) was 6.62 +/- 0.20 (n = 4). Treatment with glucose before ischemia markedly lowered the pH(e) (5.88 +/- 0.17) but not pH(i) (6.83 +/- 0.03, n = 4) measured 1 h after ischemia. In the ischemic cortex of animals made hypoglycemic by pretreatment with insulin, neither pH(e) (7.25 +/- 0.06) nor pH(i) (6.99 +/- 0.13, n = 4) decreased. The demonstrated difference in pH(i) and pH(e) indicates that some cells remained sufficiently functional to maintain a plasma membrane gradient of protons within the evolving infarct. If the calculated pH(i) values accurately reflect the true pH(i) of cells within zones of severe focal ischemia, then cerebral infarction can proceed at pH(i) levels not greatly altered from normal.