Kindling as a neuronal plasticity (Effect of dentate nucleus lesion upon amygdaloid kindling in cats)

用杏仁核点燃法研究猫小脑齿状核是否参与了大脑神经元的可塑性。在这项研究中，我们研究了11只猫在对照条件下和对侧小脑齿状损伤后杏仁核核点燃过程中的行为变化、癫痫样事件的发生和放电后的持续时间。损伤组6只动物中有5只受到第一次刺激，对照组5只动物中有1只受到第二次刺激。损伤组的杏仁核和海马原发部位的棘峰数量开始增加，但在点燃后期，与对照组相比，棘峰数量减少。损伤组海马第二部位的尖峰增加较多。因此，小脑齿状病变有利于继发性癫痫的发生。观察大鼠杏仁体发育过程中海马细胞外谷氨酸（Glu）浓度与癫痫发作相关的变化。刺激后细胞外谷氨酸水平升高，并迅速恢复到基线水平。在部分点燃大鼠（阶段3）中，刺激后第一分钟的细胞外Glu水平是基线的2.5-3.5倍，而完全点燃大鼠的Glu水平则增加了约5倍。然后，我们同时监测脑透析液中海马细胞外谷氨酸（Glu）和γ -氨基丁酸（GABA）浓度与癫痫发作相关的变化，以阐明Glu和GABA在点燃发生中的作用。细胞外GABA浓度逐渐升高，在刺激后15-20分钟达到平台水平，每个阶段持续数小时。GABA水平在部分点燃阶段是基线的1.5倍左右，在完全点燃阶段是基线的2.5倍左右。进行性、短暂性和刺激诱导的细胞外谷氨酸水平的增强，加上双侧海马腹侧细胞外GABA水平的长期升高，导致兴奋性和抑制性神经元系统之间的过度同步和不平衡，导致癫痫活动的过度传播，最终导致杏仁核点燃的继发性全身性癫痫发作。少

Amygdaloid kindling is used to investigate whether the cerebellar dentate nucleus participate in the neuronal plasticity of the cerebrum in cats. In this study we examined the behavioral change, the occurrence of epileptiform events and duration of afterdischarge during amygdaloid kindling under control conditions and after a contralateral cerebellar dentate lesion in 11 cats. The first stimulation induced stage 2 in five animals out of six in lesioned group, but one of five in control group. The numbers of spikes on the primary site of the amygdala and hippocampus in the lesionde group increased at first, however on the later stage of kindling, those were decreased compared to the control gourp. The spikes on the secondary site of the hippocampus increased more in the lesioned group. Threfore cerebellar dentate lesion facillitated the secondary epileptogenesis. The seizure-related changes of extracellular hippocampal glutamate (Glu) concentration during the development of amygdaloid k … More indling were monitored. The extracellular Glu level enhanced after stimulus and returned rapidly to baseline. In partially kindled rats (stage 3), the extracellular Glu level during the first minutes post stimulus was 2.5-3.5 fold that of the baseline, while fully kindled rats exhibited about a 5-fold increase in the Glu level.Then, we simultaneously monitored the seizure-related changes in extracellular hippocampal glutamate (Glu) and gamma-aminobutyric acid (GABA) concentration in brain dialysates in order to clarify the role of Glu and GABA in the development of kindling. Extracellular GABA concentration gradually, reaching a plateau level at 15-20 min.and lasting for several hours after stimulus at each stage. The enhancement of GABA level was about 1.5 times that of the baseline in the partially kindled stage, and was about 2.5 times of the baseline in the fullly kindled stage. The progressive, transient and stimulus-induced enhancement of extracellular Glu levels combined with long-lasting elevation of extracellular GABA levels in the bilateral ventral hippocampi results in hypersynchrony and imbalance between the excitatory and inhibitory neuronal systems, causing excessive propagation of seizure activity, culminating in the secondary generalized seizure of amygdaloid kindling. Less