Background

Temporal lobe epilepsy (TLE) is the most common intractable epilepsy in adults, and elucidation of the underlying pathological mechanisms is needed. Voltage-gated chloride channels (ClC) play diverse physiological roles in neurons. However, less is known regarding their functions in the epilepogenesis of TLE.

Methods

ClC-mediated current and the spontaneous inhibitory synaptic currents (sIPSC) in hippocampal neurons of epileptic lesions were investigated by electrophysiological recording. The EEG data were analyzed by Z-scored wavelet and Fourier transformations. The expression of ClC-3, a member of ClC gene family, was detected by immunostaining and western blot.

Findings

ClC-mediated current was increased in the hippocampal neurons of chronic TLE mice. Application of chloride channel blockers, NPPB (5-Nitro-2- [3-phenylpropylamino] benzoic acid) and DIDS (4,4’-Diisothiocyanato-2,2’-stilbenedisulfonic acid disodium salt) reduced ClC-mediated current and increased inhibitory synaptic transmission in TLE mice. NPPB and DIDS reduced the seizure frequency and the average absolute power of ictal high-frequency oscillations (HFOs, 80-500 Hz) in TLE mice. In addition, both drugs induced outwardly rectified currents, which might be tonic inhibitory currents in the hippocampal neurons of TLE patients. Furthermore, the expression of ClC-3 was increased in the hippocampus of TLE mice and patients and positively correlated with both the absolute power and number of ictal HFOs per seizure in the sclerotic hippocampus.

Interpretation

These data suggest that ClC participate in the epilepogenetic process of TLE and the inhibition of ClC may have anti-epileptic effect.

Funding

This work was supported by National Natural Science Foundation of China (No. 81601143, No. 81771217).

中文翻译：

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电压门控氯离子通道在颞叶癫痫发生中的作用

背景

颞叶癫痫（TLE）是成人中最常见的难治性癫痫，需要阐明其潜在的病理机制。电压门控氯离子通道 (ClC) 在神经元中发挥多种生理作用。然而，人们对它们在 TLE 癫痫发生中的功能知之甚少。

方法

通过电生理记录研究癫痫病灶海马神经元中 ClC 介导的电流和自发抑制突触电流 (sIPSC)。通过 Z 评分小波和傅里叶变换对 EEG 数据进行分析。通过免疫染色和Western blot检测ClC基因家族成员ClC-3的表达。

发现

慢性 TLE 小鼠海马神经元中 ClC 介导的电流增加。使用氯离子通道阻滞剂 NPPB（5-硝基-2-[3-苯基丙氨基]苯甲酸）和 DIDS（4,4'-二异硫氰酸基-2,2'-二苯乙烯二磺酸二钠盐）可减少 ClC 介导的电流并增加抑制TLE 小鼠的突触传递。NPPB 和 DIDS 降低了 TLE 小鼠的癫痫发作频率和发作期高频振荡（HFO，80-500 Hz）的平均绝对功率。此外，两种药物都会诱导外向整流电流，这可能是 TLE 患者海马神经元的强直抑制电流。此外，TLE 小鼠和患者海马中 ClC-3 的表达增加，并且与硬化海马中每次发作的发作性 HFO 的绝对功率和数量呈正相关。

解释

这些数据提示ClC参与了TLE的癫痫发生过程，抑制ClC可能具有抗癫痫作用。

资金

该工作得到了国家自然科学基金（No.81601143、No.81771217）的资助。