Inward rectifier K+ channel Kir2.3 (IRK3) in reactive astrocytes from adult rat brain
Inward rectifier K+ channel Kir2.3 (IRK3) in reactive astrocytes from adult rat brain
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DOI：
10.1002/1098-1136(200008)31:2
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发表时间：
2000-08
期刊：
影响因子：
6.2
通讯作者：
Pablo Perillan;Xing Li;Eric A Potts;Mingkui Chen;D. Bredt;J. Simard
中科院分区：
文献类型：
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作者：
Pablo Perillan;Xing Li;Eric A Potts;Mingkui Chen;D. Bredt;J. Simard
参与中枢神经系统 K+ 空间缓冲的星形胶质细胞内向整流 K+ 通道已被广泛研究，但具体基因产物尚未完全鉴定。我们研究了来自成年大鼠大脑的原代培养的星状和多边形形态的反应性星形胶质细胞，以及来自新生大鼠大脑的星状星形胶质细胞。细胞贴附斑块的单通道记录显示，多边形反应性星形胶质细胞仅表达一种11-15 pS的超极化激活单通道电导，其开放概率与电压无关，而星状反应性和星状新生星形胶质细胞表现出两种电导，11-15 pS和24-27 pS。所有三种亚型星形胶质细胞均表现出超极化激活的宏观内向 K+ 电流，该电流具有强烈的整流性，并被传统但非穿孔贴片全细胞记录过程中引入的 1 mM 细胞内 Mg2+ 消除。该 Mg2+ 敏感电流包含多边形反应性星形胶质细胞中的总内向整流器电流，但仅占星形反应性星形胶质细胞和星形新生星形胶质细胞中的内向整流器电流的一小部分。由于单通道电导为 11-15 pS 且与电压无关的强整流内向整流 K+ 通道与 Kir2.3 (IRK3) 的特征一致，因此我们使用抗 Kir2.3 和抗胶质纤维酸性蛋白抗体进行了免疫荧光实验。两种抗体共定位于原代培养物中星形胶质细胞的所有三种亚型以及脑和明胶海绵植入物内原位反应性星形胶质细胞。我们的数据表明，来自成年和新生大鼠脑的多边形和星形形态的星形胶质细胞在体内和体外均表达 Kir2.3。无论细胞形态或来源组织的起源年龄如何，Kir2.3 的组成型表达表明该通道在星形胶质细胞中具有重要的功能作用。 GLIA 31:181–192, 2000。© 2000 Wiley-Liss, Inc.
Astrocytic inward rectifying K+ channels that participate in K+ spatial buffering in the central nervous system have been extensively investigated, but specific gene products have not been fully identified. We studied primary cultured reactive astrocytes of stellate and polygonal morphology from adult rat brains, as well as stellate astrocytes from neonatal rat brains. Single‐channel recordings of cell‐attached patches revealed that polygonal reactive astrocytes expressed only one hyperpolarization‐activated single‐channel conductance of 11–15 pS whose open probability was independent of voltage, whereas stellate reactive and stellate neonatal astrocytes exhibited two conductances, 11–15 pS and 24–27 pS. All three subtypes of astrocytes exhibited a hyperpolarization‐activated macroscopic inward K+ current that was strongly rectifying and was abrogated by 1 mM intracellular Mg2+ introduced during conventional but not perforated patch whole‐cell recording. This Mg2+‐sensitive current comprised the total inward rectifier current in polygonal reactive astrocytes, but only a fraction of the inward rectifier current in stellate reactive and stellate neonatal astrocytes. Because a strongly rectifying, inward rectifier K+ channel with a single‐channel conductance of 11–15 pS that is voltage independent is consistent with features of Kir2.3 (IRK3), we performed immunofluorescence experiments with anti‐Kir2.3 and anti‐glial fibrillary acidic protein antibodies. Both antibodies co‐localized to all three subtypes of astrocytes in primary culture and to reactive astrocytes in situ within brain and gelatin sponge implants. Our data indicate that astrocytes of both polygonal and stellate morphology, from both adult and neonatal rat brain, express Kir2.3 both in vivo and in vitro. Constitutive expression of Kir2.3 regardless of cell morphology or age of origin of the source tissue suggests an important functional role for this channel in astrocytes. GLIA 31:181–192, 2000. © 2000 Wiley‐Liss, Inc.