红藻氨酸诱导大鼠癫痫发作的电生理机制研究

目的　探讨红藻氨酸 ( KA)诱导大鼠复杂部分性癫痫发作的 EEG特点以及可能的电生理起搏点位置。方法　在立体定位指引下 ,将 EEG记录电极植入 1 2只大鼠双侧海马、额叶皮质或杏仁核中 ,其中 8只为实验组 ,4只为对照组。手术后 1周在大鼠清醒状态下 ,连续描记 KA或盐水注射后 EEG 1 2 0 min,观察 EEG波形、波幅以及频率的变化特点并记录每次电发作的起搏点位置。结果　 ( 1 ) KA注射后大鼠 EEG表现出多种形式的放电波形 ,典型波形有单棘波、多棘波、多相棘波、正相棘波、棘节律、节律性慢波、棘慢波等。 ( 2 )大鼠在凝视发作以及自动症发作时海马、杏仁核和额叶皮质均有异常放电。 ( 3) KA注射后大鼠电发作起搏点不固定。 ( 4 )各导放电频率多数情况下一致 ,偶有不一致现象。 ( 5 )存在亚临床放电。结论　 ( 1 ) KA注射后大鼠 EEG表现为多种形式的电发作活动 ;( 2 )大鼠在复杂部分性发作过程中不仅有边缘系统参与 ,也有边缘外额叶皮质参与 ;( 3)KA模型中 ,电发作起搏点不固定 ,KA注射后大鼠脑内可能存在一个异常的神经元网络 ,在网络中存在放电不均衡现象。

Electrophysiologic Mechanisms of Seizures Induced by Kainic Acid in Rat

Objective To explore the characterestics of EEG during seizures induced by kainic acid (KA) in rat and possible focus of seizure onset.Methods The depth electrodes were chronically implanted under stereotaxic guidance into bilateral hippocampi, frontal cortices or amygdalae in 12 rats. One week after, KA was injected i.p. in 8 unanaesthetized rats while normal saline in the other 4, and EEG was recorded continuously for the next 120 min.Results (1) Following KA treatment, EEG recordings displayed various waveform seizures, such as random spikes, polyspikes, polyphasic spikes, positive spikes, rhythmic spikes, rhythmic slow waves, and spike wave complexes. (2) When the rats suffered staring and automatisms spells, hippocampus, frontal cortex and amygdala all exhibited abnormal discharges. (3) No rats had exclusively focal onset seizures. During the later seizures, the common pattern seizure onset was the synchronized appearance of EEG changes at multiple recording sites (diffuse onset). (4) The discharge frequency was the same among the different leads.(5)There were subclinical discharges in KA model.Conclusions (1) EEG recordings showed various waveform seizures after KA treatment, which suggested that neuron activity in rat brain was very complicated during seizures. (2) Limbic areas and extralimbic frontal cortex were both involved in complex partialseizure.(3) In KA model, there was no single or fixed focus of seizure onset. The seizure was likely to arise from a distributed network of a large epileptogenic circuit. In the network, discharges sometimes were unbalanced.