Electrophysiological characteristics of sodium channel in pyramidal neurons in fragile X mental retardation 1 knockout mice

Objective To determine the electrophysiological changes of sodium current in hippocampal pyramidal neurons in fragile X mental retardation 1 (FMR1) knockout (KO) mice and wild-type (WT) mice, and to investigate the effect of the change of neuronal excitability on epilepsy in FMR1 KO mice. Methods The acute isolated technique was used to obtain the pyramidal neurons in FMR1 KO mice and WT mice. The electrophysiological characteristics, such as the activation, inactivation and recovery of sodium channels were recorded by patch clamp technique. Results The current density of pyramidal neurons in FMR1 KO mice was 0.2932±0.106 (nA/pF) , which was higher than 0.1260 ± 0.054 (nA/pF) of WT mice, P<0.05, and the difference was statistically significant. There were no statistically significant differences in the electrophysiological characteristics of activation, inactivation and recovery between the KO mice and WT mice. Conclusion The enhanced excitability of pyramidal neurons caused by increased current density might contribute to the susceptibility of epilepsy in FMR1 KO mice. Key words: Fragile X syndrome; Epilepsy; Neurons; Sodium channels; Patch clamp