Giaume C, Fromaget C, el Aoumari A, Cordier J, Glowinski J, Gros D
INSERM U114 Collége de France, Paris.
Neuron. 1991 Jan;6(1):133-43. doi: 10.1016/0896-6273(91)90128-m.
Currents from gap junction channels were recorded from pairs of astrocytes in primary culture using the double whole-cell recording technique. In weakly coupled pairs, single-channel events could be resolved without pharmacological uncoupling treatment. Under these conditions, unitary conductance was 56 +/- 7 pS, and except for multiples of this value, no other level of conductance was observed consistently. To characterize the type of junctional protein constituting astrocyte gap junction channels, immunological and biochemical experiments were carried out on the same material. Specific cDNA probes for three connexins identified in mammals (Cx26, Cx32, and Cx43) showed that only Cx43 mRNA was expressed in cultured astrocytes. The presence of Cx43 protein in cultured astrocytes was demonstrated by immunoblotting, immunofluorescence, and immunogold labeling using anti-peptide antibodies specific to Cx43. These results strongly suggest that gap junctions in astrocytes have a 50-60 pS unitary conductance associated with channels composed of Cx43 protein.
使用双全细胞记录技术，从原代培养的星形胶质细胞对中记录缝隙连接通道的电流。在弱耦合的细胞对中，无需进行药理学解偶联处理就能分辨出单通道事件。在这些条件下，单通道电导为56±7 pS，除了该值的倍数外，未持续观察到其他电导水平。为了表征构成星形胶质细胞缝隙连接通道的连接蛋白类型，对相同材料进行了免疫学和生化实验。针对在哺乳动物中鉴定出的三种连接蛋白（Cx26、Cx32和Cx43）的特异性cDNA探针显示，培养的星形胶质细胞中仅表达Cx43 mRNA。使用对Cx43特异的抗肽抗体，通过免疫印迹、免疫荧光和免疫金标记证实了培养的星形胶质细胞中存在Cx43蛋白。这些结果强烈表明，星形胶质细胞中的缝隙连接具有与由Cx43蛋白组成的通道相关的50 - 60 pS单通道电导。
