电突触与遗传性癫痫易感大鼠惊厥发病机制的关系

The relations between electrical synapse and the mechanism of epilepsy in genetical epilepsy prone rat

目的探讨电突触在癫痫发病机制中的作用。方法将反义缝隙连接蛋白（Ｃｘ３２）寡聚核苷酸（ｏｌｉｇｏｄｅｏｘｙｎｕｃｌｅｏｔｉｄｅ，ＯＤＮ）注射Ｐ７７ＰＭＣ大鼠侧脑室，观察其对大鼠惊厥的影响，并观察其离体脑片电生理实验中对神经元同步化放电的影响，同时采用原位杂交和免疫组织化学的方法证实反义Ｃｘ３２ＯＤＮ对脑内Ｃｘ３２ｍＲＮＡ表达及Ｃｘ３２蛋白合成的影响。结果（１）侧脑室注射反义Ｃｘ３２ＯＤＮ大鼠铃声刺激后惊厥评分明显低于对照组（Ｐ＜００１）。（２）在给予反义Ｃｘ３２ＯＤＮ预先处理的Ｐ７７ＰＭＣ大鼠的颞叶脑片内嗅皮层上，用低Ｍｇ２＋液诱发不出典型的癫痫样放电，其放电频率和幅度与对照组比较分别降低３０％和７０％。（３）反义Ｃｘ３２ＯＤＮ能明显抑制Ｐ７７ＰＭＣ大鼠脑内Ｃｘ３２ｍＲＮＡ的表达及Ｃｘ３２蛋白合成。结论从整体和离体水平证实电突触参与了惊厥时神经元的同步化放电过程。

Objective To investigate the role of gap junction protein Cx32 formed electrical synapses in the pathogenesis of epilepsy. Methods Antisense oligodeoxynucleotides (ODN) techniques, intracerebroventricular injection, neuronal discharges in temporal cortex slices, in situ hybridization and immunohistochemistry were used. Results An antisense ODN for Cx32 100 μg was intracerebroventricularly injected once daily, for 3 days to P77PMC rat. The audiogenic seizure scores were significantly lowered as compared with the corresponding sense ODN (or PBS) treated control groups. Moreover, in the enterhinal cortex of the temporal cortex slice of antisense ODN treated P77PMC rat, the typical seizure like events and the late recurrent discharges were not induced by lower Mg 2+ solution. The frequency and amplitude of neuronal discharges were decreased as compared with the control group. In situ hybridization and immunohistochemistry studies confirmed that Cx32 mRNA expression and Cx32 synthesis were also inhibited by Cx32 antisense ODN in P77PMC rat brain. Conclusion Our results confirmed that gap junction formed electrical synapse between neurons plays an important role in the development of synchronization of neuronal discharges in vivo and in vitro.