CAPN2 and epilepsy: Since our previous study (Chen et al., 2017) and studies of other researchers (Huang et al., 2012; Baek et al., 2016) have already shown that KCC2 is a key protein in the onset of seizure, and its functional down-regulation plays a decisive role in the formation and development of epileptiform neuronal bursting discharges and subsequent epilepsy, our current study may provide a possible mechanism that enhanced m-calpain activation during convulsant stimulation facilitates seizure induction by increasing KCC2 down-regulation.