Author/Authors :
Ghafouri، Samireh نويسنده Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran , , Fathollahi، Yaghoub نويسنده Department of Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran , , Semnanian، Saeed نويسنده Department of Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran , , Shojaei، Amir نويسنده Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran , , Mirnajafi-zadeh، Javad نويسنده Physiology Department, Faculty of Medicine, Tarbiat Modares University, Tehran, Iran. Mirnajafi-zadeh, Javad
Abstract :
Objective: Low-frequency stimulation (LFS) exerts suppressive effects in kindled animals. It
is believed that overstimulated glutamatergic and decreased GABAergic transmission have
long been associated with seizure activity. In this study, we investigated the effect of electrical
LFS on different parameters of spontaneous excitatory and inhibitory post-synaptic currents
(sEPSCs and sIPSCs) in hippocampal CA1 pyramidal cells in kindled animals.
Materials and Methods: In this experimental study, rats were kindled by electrical stimulation
of the hippocampal CA1 area in a semi-rapid manner (12 stimulations/day). The
animals were considered fully kindled when they showed stage 5 seizures on three consecutive
days. One group of animals received LFS 4 times at 30 seconds, 6 hours, 18 and
24 hours following the last kindling stimulation. Each LFS consisted of 4 packages at 5
minutes intervals. Each package of LFS consisted of 200 pulses at 1 Hz and each monophasic
square wave pulse duration was 0.1 millisecond. At 2-3 hours post-LFS, acute
hippocampal slices were prepared and a whole cell patch clamp recording was performed
in all animals to measure the different parameters of sEPSCs and sIPSCs.
Results: In kindled animals, the inter-event interval (as an index of occurrence) of sEPSCs
decreased, whereas sIPSC increased. In addition, the decay time constant of sIPSCs
as an index of the duration of its activity decreased compared to the control group. There
was no significant difference in other parameters between the kindled and control groups.
Application of LFS in kindled animals prevented the observed changes. There was no significant
difference between the measured parameters in kindled+LFS and control groups.
Conclusion: LFS application may prevent seizure-induced increase in the occurrence
of sEPSCs and seizure-induced decrease in occurrence and activity duration of sIPSCs.
