Behavioral Consequences of hippocampal epileptogenesis in adult male rat

  Behavioral disorders such as anxiety and depression are often experienced by several forms of epilepsy. Since the kindling process, as a model of temporal lobe epilepsy produces behavioral impairment, the present research was designed to evaluate the anxiety and depressive like behaviors induced by hippocampal rapid kindling.
Material & Twenty-one male wistar rats were randomly divided into 3 groups: control (intact animals), sham operation (without any stimulation) and kindled animals. Seven days after electrode implantation in CA1 region of hippocampus, threshold intensity was determined. In the next day, animals in the kindled group were stimulated in a rapid kindling manner (12 times/day) for six days with the following protocol: 3s train of 50 Hz monophasic pulses of 1ms duration with the threshold intensity at 10 minutes intervals. Finally anxiety and depressive like behaviors were assessed respectively by the elevated plus maze (EPM), open field in the 6th day and forced swim test (FST) in the following day. The results of this experiment showed that the hippocampal kindling increased open arms (OAs) entries percentage (P=0.005) and OAs exploration percentage (P=0.02), jumping from apparatus and rearing in open field box compared to sham group (P=0.006). Also the latency to first immobility in kindled group decreased significantly (P=0.000) whereas the duration of immobility increased significantly in comparison to the sham group (P=0.000). It seems that kindling enhances excitatory processes or disturbs neuronal inhibition which leads to emotional disturbances such as anxiety and depressive like behavior in animals