Nakamura T, Minamisawa H, Katayama Y, Ueda M, Terashi A, Nakamura K, Kudo Y
Laboratory of Cellular Neurobiology, School of Life Science, Tokyo University of Pharmacy and Life Science, Japan.
Neuroscience. 1999 Jan;88(1):57-67. doi: 10.1016/s0306-4522(98)00207-3.
The crucial role of free cytosolic Ca2+ in ischemic neuronal damage has been studied in recent years. In the present report, changes in the intracellular Ca2+ concentration in the hippocampal CA1 area during transient global ischemia and reperfusion were measured using in vivo Ca2+ fluorometry with fura-2 in the four-vessel occlusion and reperfusion model in halothane-anesthetized rats. Marked changes were seen during 10-min global ischemia, with the intracellular Ca2+ concentration increasing gradually following application of the ischemic insult and rapidly about 2 min after the beginning of ischemia, and continuing to increase until reperfusion. On reperfusion, the intracellular Ca2+ concentration began to decrease and returned to the pre-ischemic level within 15 min. Induction of severe global ischemia was confirmed by the complete suppression of synaptic activity and the decrease in hippocampal temperature in the CA1 area. After seven days, CA1 pyramidal cell loss was observed histopathologically in the same rats which had undergone measurement of the intracellular Ca2+ concentration changes. In the present study, a temporal profile of the free cytosolic Ca2+ dynamics during ischemic and early post-ischemic period was determined in vivo. The results demonstrate that the intracellular Ca2+ concentration in the hippocampal CA1 area is transiently and markedly increased during a brief ischemia-inducing delayed neuronal death, implying that Ca2+ overload during cerebral ischemia is a possible cause of the delayed cell death of CA1 pyramidal neurons.
近年来，游离胞质Ca2+在缺血性神经元损伤中的关键作用已得到研究。在本报告中，采用活体Ca2+荧光测定法，利用氟罗红-2，在氟烷麻醉的大鼠四血管闭塞和再灌注模型中，测量了短暂性全脑缺血和再灌注期间海马CA1区细胞内Ca2+浓度的变化。在10分钟的全脑缺血期间观察到明显变化，缺血损伤后细胞内Ca2+浓度逐渐升高，缺血开始约2分钟后迅速升高，并持续升高直至再灌注。再灌注时，细胞内Ca2+浓度开始下降，并在15分钟内恢复到缺血前水平。通过完全抑制突触活动和CA1区海马温度降低，证实了严重全脑缺血的诱导。七天后，在同一组经历了细胞内Ca2+浓度变化测量的大鼠中，通过组织病理学观察到CA1锥体细胞丢失。在本研究中，在体内确定了缺血和缺血后早期游离胞质Ca2+动力学的时间变化情况。结果表明，在短暂缺血诱导延迟性神经元死亡期间，海马CA1区细胞内Ca2+浓度短暂且显著升高，这意味着脑缺血期间的Ca2+超载可能是CA1锥体细胞延迟性死亡的原因。
