Service de Neurochirurgie, Centre Hospitalier Sainte-Anne, Paris, France.
Hippocampus. 2011 Mar;21(3):334-43. doi: 10.1002/hipo.20795.
Epilepsy-associated changes of the anatomical organization of the dentate gyrus and hilus may play a critical role in the initiation and propagation of seizures in mesial temporal lobe epilepsy (MTLE). This study evaluated the role of longitudinal projections in the propagation of hippocampal paroxysmal discharges (HPD) in dorsal hippocampus by performing a selective transection in a mouse model for MTLE obtained by a single unilateral intrahippocampal injection of kainic acid (KA). Full transections of the dentate gyrus and hilus were performed in the transverse axis at 22 days after KA injection when spontaneous HPD were fully developed. They: (i) significantly reduced the occurrence of HPD; (ii) increased their duration at the KA injection site; (iii) abolished their spread along the longitudinal axis of the hippocampal formation and; (iv) limited granule cell dispersion (GCD) of the dentate gyrus posterior to the transection. These data suggest that: (i) longitudinal projections through the dentate gyrus and hilus are involved in HPD spread; (ii) distant hippocampal circuits participate in the generation and cessation of HPD and; (iii) GCD requires continuous HPD to develop, even when seizures are established. Our data reveal a critical role for longitudinal projections in the generation and spread of hippocampal seizures.
癫痫相关的齿状回和门区解剖组织变化可能在颞叶内侧癫痫（MTLE）的发作起始和传播中起关键作用。本研究通过对单侧海马内注射海人酸（KA）建立的 MTLE 小鼠模型进行选择性横断，评估了纵向投射在海马阵发性放电（HPD）传播中的作用。在 KA 注射后 22 天，当自发 HPD 完全发展时，在齿状回和门区的横切面上进行完全横断。结果发现：（i）显著降低 HPD 的发生；（ii）增加了在 KA 注射部位的持续时间；（iii）消除了它们沿海马结构的长轴传播；（iv）限制了横断后齿状回颗粒细胞弥散（GCD）。这些数据表明：（i）穿过齿状回和门区的纵向投射参与了 HPD 的传播；（ii）远隔海马回路参与了 HPD 的产生和停止；（iii）即使癫痫已经建立，GCD 的发展也需要持续的 HPD。我们的数据揭示了纵向投射在海马发作的产生和传播中的关键作用。
