| Part I The study on the stimulate duration of low-frequency stimulation that inhibit amygdaloid-kindling seizures in ratsObjectiveThe present work was undertaken in order to study the effects of LFS when delivered different stimulus duration (especially after discharge duration in electroencephalogram), using amygdaloid-kindling seizures ra modelst in rats.Methods:1. The electrode placement operation and amygdaloid-kindling seizures model.After exposure of skull, electrodes were implanted into the right basolateral amygdala. It was fixed to the skull and connects to a miniature socket. Before the trial, we measure the after discharge threshold in rats. According to the average threshold value, rats were divided into six groups and given an electric stimulation every day.(1s and1ms wave wide,100-300μA,60Hz).2. LFS with different stimulation duration on kindling acquisition and kindled seizures.In kindling acquisition and kindled seizures experiments, low frequency electrical stimulation (0.1ms wave width,150μA1Hz) rats and observe the seizure severity and record electroencephalogram.Results:1.Low frequency electric stimulation for15minutes and30minutes can significantly slowed the progression of behavioral seizure stages and reduced mean ADD during kindling acquisition and kindled seizures while LFS for1minutes and5minutes have no effect.LFS was intermittently delivered for15minutes cannot inhibit the seizure progress.2. Low frequency electric stimulation for15minutes and30minutes can significantly slowed the progression of behavioral seizure stages and reduced mean ADD during kindled seizure in rats and reduced the power in delta.Conclusions:Consecutive15min and30min is necessary for LFS to inhibit amygdaloid-kindling seizure in rats, indicating the stimulation duration may be a key fact affecting the clinical effect of LFS on epilepsy. Part II The study on the stimulate mode of low frequency stimulation that inhibit amygdaloid-kindling seizures in ratsObjective:The present work was undertaken in order to study which mode of stimulation is more suitable for low frequency electric stimulation play the antiepileptic effect in amygdaloid-kindling seizures rats,hoping to help chossing LFS in clinical treatment of refractory epilepsy.Methods:1. The electrode placement operation and amygdaloid-kindling seizures modelAfter exposure of skull, electrodes were implanted into the right basolateral amygdala. It was fixed to the skull and connects to a miniature socket. Before the trial, we measure the after discharge threshold in rats. According to the average threshold value, rats were divided into five groups and given an electric stimulation (1s and1ms wave wide,100-300μA,60Hz).2. LFS with different stimulation duration on kindling acquisitionIn kindling acquisition experiments, low frequency electrical stimulation (0.1ms wave width,150μA,1Hz) rats and observes the seizure severity and record electroencephalogram rats.Results:1. The posttreatment-LFS mode reduced the seizure stages and shorten the after discharge duration during kindling acquisition. The pretreatment-LFS mode cannot effectively antiepilepsy in rats and even reverse the inhibit effect of seizures when the posttreatment-LFS mode exist alone.2. In posttreatment-LFS mode, LFS were only delivered for five days can significantly slowed the progression of behavioral seizure stages and the inhibit effect main on seizure stage1-3. Conclusions:LFS has a mode-dependent effect that inhibits amygdaloid-kindling seizures in rats. The posttreatment-LFS mode has a antiepileptic effect while the posttreatment-LFS mode has no effect. Part III The study on the inhibitory effects of LFS at the external segment of the globus pallid us on amygdaloid-kindling seizures and pentylenetetrazole (PTZ)-induced seizures in ratsObjective:The present work was undertaken in order to study the effect of low frequency electric stimulation delivered into globus pallidus using amygdaloid-kindling seizures model and PTZ-kindled seizures model.Methods:1. The electrode placement operation and amygdaloid-kindling seizures modelAfter exposure of skull, electrodes was implanted into the right basolateral amygdala and left the external segment of the globus pallidus.It were fixed to the skull and connect to a miniature socket. Before the trial, we measure the after discharge threshold in rats. According to the average threshold value, rats were divided into there groups and given an electric stimulation (1s and1ms wave wide,100-300μA,60Hz).In kindling acquisition experiments, low frequency electrical stimulation (0.1ms wave width,150μA,1Hz) and high frequency electrical stimulation were delivered to rats and observe the seizure severity.2. Effect of LFS on PTZ-kindled seizuresTo induce kindling, a subconvulsant dose (35mg/kg) of pentylenetetrazole was i.p. injected every48h.Low frequency electrical stimulation (0.1ms wave width,150μA,1Hz) was delivered to rats.Results:1. In kindling animals, LFS delivered immediately after cessation of the kindling stimulus inhibited the seizure stages and shorten the after discharge duration during kindling acquisition.2. In PTZ-induced seizures rats, LFS cannot inhibited the seizure stages, but significantly prolong animal seizure latency.Conclusions:When select the appropriate stimulus parameters, DBS at the external segment of the globus pallidus can effectively suppress seizure. |
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