[Characterization of electrophysiological properties and changes in gene expression in basket cells during the postnatal development of mouse prefrontal cortex].

This study aims to explore the electrophysiological properties and changes in gene expression of basket cells, a unique population of GABAergic interneurons expressing parvalbumin (PV), during the postnatal development of mouse prefrontal cortex (PFC). Toward this goal, we took use of the G42 transgenic mouse line which specifically expresses enhanced green fluorescent protein (EGFP) in basket cells. The brain slices of PFC were prepared from the postnatal 7 (P7), 14 (P14) and 21 days (P42) G42 mice and whole-cell patch clamp recording was performed in basket cells. In addition, we sorted the basket cells by flow cytometry and analyzed their transcription profiling on P7, P14, and P21 using RNA-seq technology. The results showed that the resting membrane potential and membrane input resistance decreased gradually from P7 to P21. The amplitude and duration of action potential of basket cells increased and decreased from P7 to P21, respectively. In contrast, the threshold of action potential of basket cells did not have a significant change from P7 to P21. The frequency of spontaneous excitatory postsynaptic currents (sEPSCs) of basket cells increased gradually, while the amplitudes of sEPSCs of basket cells remained constant from P7 to P21. RNA sequencing from basket cells revealed that the expression of 22 and 660 genes was upregulated and downregulated from P7 to P14, respectively. By contrast, the expression of 107 and 69 genes was upregulated and downregulated from P14 to P21, respectively. The differentially expressed genes in basket cells from P7 to P21 were significantly enriched in pathways such as neuron apoptotic process, mRNA processing, Golgi vesicle transport and axon guidance. Altogether, we characterized electrophysiological properties and changes in gene expression of basket cells during the postnatal development in mouse PFC. These results provide insight into the mechanisms underlying the development of basket cells in mouse cortex.