Hypoxia increases calcium flux through cortical neuron glutamate receptors via protein kinase C
Hypoxia increases calcium flux through cortical neuron glutamate receptors via protein kinase C
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DOI：
10.1046/j.1471-4159.2003.02203.x
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发表时间：
2004-02-01
影响因子：
4.7
通讯作者：
Ferriero, DM
中科院分区：
文献类型：
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作者：
Bickler, PE;Fahlman, CS;Ferriero, DM
本文研究了缺氧30 s至10 min（PO_2 -10 mmHg）对小鼠皮层神经元谷氨酸受体活性的影响。在0.1 mM Mg 2+和10 μ M甘氨酸存在下，应用1 mM谷氨酸或100 μ M N-甲基-D-天冬氨酸（NMDA）10 s后，以细胞内钙浓度（[Ca 2 +]（i））的升高评估受体活性。在缺氧100秒期间，谷氨酸引起的[Ca ~（2+）]（i）变化增加26%（n = 192，p < 0.061），NMDA引起的[Ca ~（2+）]（i）变化增加74%（n = 9，p < 0.01）。缺氧10分钟后，对谷氨酸的反应比常氧时小62%，其中。增加的基础细胞内[Ca 2 +]（i）预测降低的受体活性。当神经元暴露于NMDA缺氧10分钟后，[Ca 2 +]（i）的增加比缺氧100秒后小12%，但仍比氧合神经元大53%（n = 9，p = 0.01）。神经元表达相对相似量的NR 2A、-B、-C和-D亚基。缺氧时NMDA NR 1亚基磷酸化水平升高。用蛋白激酶C（PKC）抑制剂（白屈菜红碱，10 μ M）预处理神经元可防止缺氧期间N-甲基-D-天冬氨酸受体（NMDAR）活性的增加，并减少NR 1亚基的磷酸化。这些结果表明，在缺氧的第一分钟，谷氨酸受体活性的增强介导的磷酸化的NMDARs的PKC和其他机制，可能涉及细胞内钙，限制谷氨酸受体介导的钙离子内流在较长时间的缺氧。
The effects of 30 s to 10 min hypoxia (PO2-10 mmHg) on glutamate receptor activity were studied in murine cortical neurons. Receptor activity was assessed as a rise in intracellular calcium concentration ([Ca2+](i)) following a 10 s application of 1 mM glutamate or 100 muM N-methy-D-aspartate (NMDA) in the presence of 0.1 mM Mg2+ and 10 muM glycine. Change in [Ca2+](i) elicited by glutamate increased 26% (n = 192, p < 0.061) and that to NMDA by 74% (n = 9, p < 0.01) during a 100-s period of hypoxia. After 10 min hypoxia, responses to glutamate were 62% smaller than those in normoxia, with. increased basal intracellular [Ca2+](i) predicting reduced receptor activity. When neurons were exposed to NMDA after 10 min of hypoxia, [Ca2+](i) increases were 12% smaller than after 100 s hypoxia, but still 53% larger than in oxygenated neurons (n = 9, p = 0.01). Neurons expressed relatively similar amounts of NR2A, -B, -C, and -D subunits. The phosphorylation of NMDA NR1 subunits increased during hypoxia. Pre-treatment of neurons with a protein kinase C (PKC) inhibitor (chelerythrine, 10 muM) prevented increases in N-methy-D-aspartate receptor (NMDAR) activity during hypoxia and reduced the phosphorylation of NR1 subunits. These results suggest that enhancement of glutamate receptor activity during the first minutes of hypoxia is mediated by phosphorylation of NMDARs by PKC and that other mechanisms, possibly involving intracellular calcium, limit glutamate receptor-mediated calcium influx during longer periods of hypoxia.