Azam Asgari; Saeed Semnanian; Nafiseh Atapour; Amir Shojaee; Vahid Sheybani; Seyyed Javad Mirnajafi Zadeh
Volume 23, Issue 2 , March and April 2016, , Pages 290-303
Abstract
Background and purpose: Low frequency stimulation (LFS) has anticonvulsant effect. However, its mechanism of action has not been completely determined. In the present study the effect of LFS on evoked inhibitory post synaptic GABAergic currents (eIPSC) is investigated in CA1 pyramidal neurons of the ...
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Background and purpose: Low frequency stimulation (LFS) has anticonvulsant effect. However, its mechanism of action has not been completely determined. In the present study the effect of LFS on evoked inhibitory post synaptic GABAergic currents (eIPSC) is investigated in CA1 pyramidal neurons of the hippocampus in kindled rats. Materials and Methods: In this experimental study animals were kindled through electrical stimulation of amygdala. 24 hours following fully kindling achievement in 20 Wistar rats, the effect of LFS on eIPSCs was assessed in hippocampal slices. Results: Obtained results showed that application of LFS at 200 pulses and at the intensity of 1.5 threshold, increased the amplitude and decay time constant of eIPSCs in both control and kindled rats. When 200 pulses of LFS were administered with an intensity equal to threshold, only eIPSC amplitude was increased in both control and kindled groups significantly (P<0.001). Comparing the effectiveness of LFS on control and kindled groups showed that 200 pulses of LFS at the intensity of 1.5 threshold had higher effect in control than kindled group (P<0.001). Conclusion: Results of the present study showed that LFS application increased eIPSCs parameters in a pulse number and intensity dependent manner. This increment can be considered as a possible anticonvulsant mechanism of LFS.
Amir Shojaee; Vahid Sheybani; Khadijeh Esmaeel pour; Yaser Masoumi; Seyyed Javad Mirnajafizadeh
Volume 20, Issue 4 , January and February 2014, , Pages 496-504
Abstract
Background: Low frequency stimulation (LFS) has been recently suggested as an antiepileptic method in treating the drug-resistant epileptic syndromes such as temporal lobe epilepsy. So far, in the most clinical and experimental studies, LFS has been applied to the seizure focus itself. Considering the ...
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Background: Low frequency stimulation (LFS) has been recently suggested as an antiepileptic method in treating the drug-resistant epileptic syndromes such as temporal lobe epilepsy. So far, in the most clinical and experimental studies, LFS has been applied to the seizure focus itself. Considering the role of dentate gyrus in spreading of the limbic seizures, in the present study the effect of LFS of dentate gyrus on amygdala kindling-induced seizures was investigated.
Materials and methods: To kindle the animals, using stereotaxic instrument, a tripolar electrode was inserted into right basolateral area of amygdala and a bipolar electrode was ipsilaterally placed in dentate gyrus of male Wistar rats. After a 10 days recovery period, animals divided into two groups. The animals of kindled group were received daily electrical stimulations. In kindled+LFS group, LFS was delivered to dentate gyrus 1 min after cessation of amygdala kindling stimulation. The maximum seizure stage and duration of afterdischarges were evaluated after kindling stimulation. The effect of LFS on behavioral seizure stages and afterdischarges was compared using Kruskall Wallis and repeated measures 2-way AVOVA. A P value less than 0.05 was considered as significant level.
Results: The required time to achieve a stage 5 seizure was 12 days in kindled group animals. However, animals of kindled+LFS group did not show more than stage 2 seizure following 12 days of stimulation. LFS of dentate gyrus significantly prevented the increment of behavioral seizure stages and afterdischarge duration in kindled-LFS group compared with kindled group.
Conclusion: The results of this study demonstrated that application of LFS in the dentate gyrus can be an effective therapeutic method for controlling the amygdala kindling-induced seizures. Furthermore, this study provide further evidences showing LFS of brain areas involved in spreading the seizures, other than seizure focus can have anticonvulsant affect.