Valentine Pamela A, Fremit Sonja L, Teskey G Campbell
Department of Clinical Neurosciences, Epilepsy Research Group, University of Calgary A275, 2500 University Drive N.W., Calgary, Alberta, Canada T2N 1N4.
Neurosci Lett. 2005 Nov 4;388(1):33-8. doi: 10.1016/j.neulet.2005.06.028.
Epilepsy is a family of neurological disorders that result in seizure activity that is characterized by transient hypersynchronous activation of a large population of neurons. In animal models, focal tetanic electrical stimulation of sufficient duration and intensity, can elicit epileptiform activity, that if repeated results in progressive intensification of seizure activity known as kindling. Kindling serves as a model of partial as well as secondarily generalized temporal lobe epilepsy. We utilized hippocampal kindling to provide a means of evaluating the effect of sensory stimulation on the duration and severity of the induced seizure activity. Sensory stimuli targeted either the olfactory, auditory or somatosensory systems in an attempt to retard or suppress seizure activity. To that end, rats were chronically implanted with electrodes in the CA1 region of dorsal hippocampus and kindled once daily until the seizure behaviour was fully generalized. Kindling stimulation consisted of daily application of 1-s trains of biphasic square wave pulses applied at a frequency of 60Hz, at the afterdischarge (AD) threshold. Sensory stimulation was applied 6-8s after the kindling stimulation every third day. One group of rats received a different sensory stimulus (novel) every third day, while another group was presented with the same sensory stimulus (repeated) every third day. Kindling stimulation applied to the dorsal hippocampus resulted in progression of the AD characteristics and seizure behavior, which typically developed very slowly in the early stages. The application of both the novel and repeated sensory stimulation during partial seizures (stages 1 and 2) resulted in a reduction in the seizure severity but not in the afterdischarge duration. Sensory stimulation delivered during secondarily generalized seizures (stages 4 and 5) failed to affect either parameter.
癫痫是一组神经疾病，其导致的癫痫发作活动的特征是大量神经元的短暂超同步激活。在动物模型中，足够持续时间和强度的局灶性强直电刺激可引发癫痫样活动，如果重复进行，会导致癫痫发作活动逐渐加剧，即点燃效应。点燃效应可作为部分性以及继发性全身性颞叶癫痫的模型。我们利用海马体点燃效应来评估感觉刺激对诱发的癫痫发作活动的持续时间和严重程度的影响。感觉刺激针对嗅觉、听觉或体感系统，试图延缓或抑制癫痫发作活动。为此，将大鼠长期植入背侧海马体CA1区的电极，每天点燃一次，直到癫痫发作行为完全泛化。点燃刺激包括每天在放电后（AD）阈值处以60Hz的频率施加1秒的双相方波脉冲串。每第三天在点燃刺激后6 - 8秒施加感觉刺激。一组大鼠每第三天接受不同的感觉刺激（新颖的），而另一组每第三天接受相同的感觉刺激（重复的）。施加于背侧海马体的点燃刺激导致AD特征和癫痫发作行为的进展，在早期阶段通常发展非常缓慢。在部分性癫痫发作（1期和2期）期间施加新颖和重复的感觉刺激均导致癫痫发作严重程度降低，但放电后持续时间未降低。在继发性全身性癫痫发作（4期和5期）期间施加的感觉刺激未能影响任何一个参数。
