Lateralization Effect Of Vagal Nerve Stimulation In Amygdala-kindling Rats

ObjectiveTo investigate the lateralization effect of vagal nerve stimulation in Amygdala-kindling RatsMethods24 adult rats were divided into four groups(ipsilateral,contralateral,bilateral and control group)equally.We implanted bipolar tungsten stimulating electrodes in the right amygdala in all rats.Meanwhile,we implanted bipolar tungsten stimulating electrodes in vagal nerve of the same side as the group divided before.Following induction of kindling,threshold of behavior seizure was determined by quantifying the amygdala electrode current required to evoke seizure of behavior(Racine classification 4 or 5).Once stable threshold of behavior seizure was established,VNS was programmed to deliver regular stimulation.Then threshold of behavior seizure was determined again.Eventually,we compared data between these two groups.Results20 rats finished this experiment.Mean weight of rats in the ipsilateral group,contralateral group,bilateral group and control group is(292.8±36.0)g,(311.3±17.2)g,(319.2±21.1)g,(313.6±22.3)g,respectively.Mean times to required to induce full kindling of behavior seizure in the ipsilateral group,contralateral group,bilateral group and control group is(15.3±1.3),(13.3±2.7),(14.8±1.9),(14.2±3.1),respectively.The mean threshold of behavior seizure before VNS,60 minutes after VNS and 1 week after VNS in the ipsilateral group was(370.0±42.4)?A,(385.0±35.1)?A,(400.0±42.4)?A,respectively.The mean threshold of behavior seizure before VNS,60 minutes after VNS and 1 week after VNS in the contralateral group was(355.0±47.6)?A,(371.7±61.1)?A,(376.7±61.9)?A,respectively.The mean threshold of behavior seizure before VNS,60 minutes after VNS and 1 week after VNS in the bilateral group was(338.0±61.4)?A,(312.0±29.5)?A,(308.0±43.2)?A,respectively.The mean threshold of behavior seizure before VNS,60 minutes after VNS and 1 week after VNS in the control group was(367.0±46.3)?A,(374.0±55.9)?A,(374.0±32.9)?A,respectively.ConclusionVNS can elevate threshold of behavior seizure effectively and the effect increases with the time.If the stimulation location is ipsilateral to the seizure foci,the trend of threshold increasment is more obvious.Bilateral VNS may have the effect to reduce threshold of behavior seizure.More experiments are needed to take to confirm the current outcome.