期刊
NEUROCHEMISTRY INTERNATIONAL
卷 57, 期 7, 页码 783-794出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.neuint.2010.08.016
关键词
CNS injury; Patch-clamp; K+ channels; Proliferation; Kir4.1; Astrocytes; NG2 glia
资金
- Grant Agency of the Czech Republic [305/09/0717, P303/10/1338]
- Academy of Sciences of the Czech Republic [AVOZ 50390512]
- Ministry of Education, Youth and Sports of the Czech Republic [LC554, 1M0538]
Astrocytes and NG2 glia respond to CNS injury by the formation of a glial scar. Since the changes in K+ currents in astrocytes and NG2 glia that accompany glial scar formation might influence tissue outcome by altering K+ ion homeostasis, we aimed to characterize the changes in K+ currents in hippocampal astrocytes and NG2 glia during an extended time window of reperfusion after ischemic injury. Global cerebral ischemia was induced in adult rats by bilateral, 15-min common carotid artery occlusion combined with low-pressure oxygen ventilation. Using the patch-clamp technique, we investigated the membrane properties of hippocampal astrocytes and NG2 glia in situ 2 hours, 6 hours, 1 day, 3 days, 7 days or 5 weeks after ischemia. Astrocytes in the CA1 region of the hippocampus progressively depolarized starting 3 days after ischemia, which coincided with decreased Kir4.1 protein expression in the gliotic tissue. Other K+ channels described previously in astrocytes, such as Kir2.1, Kir5.1 and TREK1, did not show any changes in their protein content in the hippocampus after ischemia: however, their expression switched from neurons to reactive astrocytes, as visualized by immunohistochemistry. NG2 glia displayed increased input resistance, decreased membrane capacitance, increased delayed outwardly rectifying and A-type K+ currents and decreased inward K+ currents 3 days after ischemia, accompanied by their proliferation. Our results show that the membrane properties of astrocytes after ischemia undergo complex alterations, which might profoundly influence the maintenance of K+ homeostasis in the damaged tissue, while NG2 glia display membrane currents typical of proliferating cells. (C) 2010 Elsevier Ltd. All rights reserved.
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