Properties of GABAA receptor-mediated actions in migrationg cortical plate cells of GAD67-GFP knock-in mice with identified birth period by in utero electroporation.

Abstract

In the development of cerebral cortex, cells derived from the ventricular zone (VZ) migrate in radial direction (radial migration), and form cortical plate (CP). It is well known that role of GABA is important for early CNS development. The radial migration may also be affected by such GABA actions. In GAD67-GFP knock-in mouse, the GABA contents in the brain decrease compared with the wild type. Therefore, in this study, we investigate the influence of the circumferential GABA concentration by using GAD67-GFP knock-in mice. To identify the cells in VZ at E14, HcRed was transfected into VZcells by means of in uteroelectroporation. Three days after the electroporation (E17), HcRed-labeledcells located in CP, intermediate zone, and VZ were counted. There was no significantdifference in distribution among genotypes. GABA_A-R mediated currentswere recorded by whole-cell recording from HcRed-expressingneurons at three days after the electroporation.Although spontaneous GABA currents were not observed, when GABA was apllied, GABA_A-R mediated current were evoked ina dose-dependent manner. There were no differences in dose-response propertiesof GABA-evoked currents among genotypes. These results suggest that the cells generatedin the VZ possess rather equivalent GABA_A-Rs and migrate radially independent of circumferential GABA concentration. [Jpn J Physiol 55 Suppl:S151 (2005)]