Müller M
Brain Research Institute, University of Zürich, Switzerland.
Pflugers Arch. 1993 Jan;422(4):418-23. doi: 10.1007/BF00374304.
We have developed an in vitro model of chronic epilepsy in order to study the consequences of prolonged periods of epileptic activity. After applying the convulsants bicuculline and/or picrotoxin to mature rat hippocampal slice cultures for 3 days, large numbers of swollen and vacuolated cells were observed throughout all hippocampal subfields. The number of dendritic spines of pyramidal cells was massively reduced. These changes were similar to those observed previously in post-mortem studies of hippocampal tissue from human epilepsy patients. Intracellular recordings from CA3 pyramidal cells revealed that spontaneous synaptic activity was greatly reduced in treated cultures. gamma-Aminobutyric acid-mediated inhibition was apparently not affected by sustained convulsant activity, although synaptic excitation was markedly depressed. Acute re-application of bicuculline to treated cultures elicited, upon stimulation of the mossy fibre tract, a typical interictal burst lasting several hundred milliseconds, with a wave form similar to those occurring in untreated cultures, but of a shorter duration. In contrast, ictal bursts (lasting tens of seconds), which always occur spontaneously in control cultures during initial perfusion of bicuculline, were not observed in treated cultures. These pathological changes were reversible when treated cultures were returned to normal medium for 1 week. The surviving cells had a healthy morphology and a normal complement of dendritic spines. Spontaneous synaptic activity was normal, and ictal bursts occurred spontaneously upon perfusion of bicuculline. The findings suggest that the morphological and functional changes are a consequence, rather than a direct cause of epilepsy.
为了研究长时间癫痫活动的后果，我们建立了一种慢性癫痫的体外模型。在将惊厥剂荷包牡丹碱和/或印防己毒素应用于成熟大鼠海马切片培养物3天后，在所有海马亚区均观察到大量肿胀和空泡化的细胞。锥体细胞的树突棘数量大幅减少。这些变化与先前在人类癫痫患者海马组织的尸检研究中观察到的变化相似。对CA3锥体细胞的细胞内记录显示，在处理过的培养物中，自发突触活动大大减少。γ-氨基丁酸介导的抑制作用显然不受持续惊厥活动的影响，尽管突触兴奋明显受到抑制。在刺激苔藓纤维束时，将荷包牡丹碱急性重新应用于处理过的培养物，会引发持续数百毫秒的典型发作间期爆发，其波形与未处理培养物中出现的波形相似，但持续时间较短。相比之下，在对照培养物中，在最初灌注荷包牡丹碱期间总是自发出现的发作性爆发（持续数十秒），在处理过的培养物中未观察到。当将处理过的培养物放回正常培养基中1周时，这些病理变化是可逆的。存活的细胞具有健康的形态和正常的树突棘数量。自发突触活动正常，在灌注荷包牡丹碱时会自发出现发作性爆发。这些发现表明，形态和功能变化是癫痫的结果，而不是直接原因。
