Rathmann Thomas, Khaleghi Ghadiri Maryam, Stummer Walter, Gorji Ali
Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany.
Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Germany.
Neuroscience. 2020 Aug 10;441:176-183. doi: 10.1016/j.neuroscience.2020.05.029. Epub 2020 May 23.
The transition of neuronal burst firing from the interictal to ictal state contributes to seizure initiation in human temporal lobe epilepsy. The low-Mg model of seizure is characterized by initial spontaneous interictal bursting events, which later developed into ictaform discharges. Both experimental and clinical studies point to a complex link between spreading depolarization (SD) and epileptiform field potentials (EFP), including SD-induced epileptic seizures. To investigate the mechanism of SD and EFP interactions, the effect of SD on the transition of interictal to ictal state in low-Mg model of seizure was studied in the rat hippocampus in vitro. After the appearance of interictal activities, SD was elicited by local application of KCl. SD significantly increased the amplitude and duration of action potentials and after-hyperpolarization, and hyperpolarized the membrane potential. Furthermore, SD significantly increased the duration of interictal activities and the threshold potentials of interictal activities. In addition, SD significantly accelerated the transition from interictal to ictal state compared to the control tissues. Ictal activities after induction of SD exhibited a significantly longer duration. This study revealed that SD accelerates interictal-to-ictal transitions and facilitates development of ictaform discharges, possibly via the enhancement of neural synchronization, and points to the potential role of SD in seizure initiation.
神经元爆发式放电从发作间期到发作期的转变有助于人类颞叶癫痫的发作起始。癫痫发作的低镁模型的特点是最初出现自发的发作间期爆发事件，随后发展为发作形式的放电。实验和临床研究均指出扩散性去极化（SD）与癫痫样场电位（EFP）之间存在复杂联系，包括SD诱发的癫痫发作。为了研究SD与EFP相互作用的机制，在体外大鼠海马中研究了SD对癫痫发作低镁模型中发作间期到发作期转变的影响。在发作间期活动出现后，通过局部应用氯化钾诱发SD。SD显著增加动作电位的幅度和持续时间以及后超极化，并使膜电位超极化。此外，SD显著增加发作间期活动的持续时间和发作间期活动的阈电位。另外，与对照组织相比，SD显著加速了从发作间期到发作期的转变。诱发SD后的发作期活动持续时间显著更长。这项研究表明，SD可能通过增强神经同步性加速发作间期到发作期的转变并促进发作形式放电的发展，并指出SD在癫痫发作起始中的潜在作用。
