Abstracts

Several studies have demonstrated a reduction of epileptiform activities in models of epilepsy after gradual cooling. More recently, there was a report of rapid termination of spontaneous epileptiform activity in humans with the application of cold saline. It may be possible to develop medical instruments for terminating seizures automatically with focal cooling after detecting epileptiform discharges on electroencephalogram (EEG). To realize such a therapy, we assembled a new cooling system with a thermoelectric (Peltier) chip and explored its performance to suppress experimental neocortical seizures. A Peltier chip (4.0x4.0 mm and 2 mm thick) was used for cooling. It was covered with a heat sink made of aluminum to which 37[ordm]C water was supplied to remove the heat absorbed by the chip. Halothane-anesthetized adult, male Sprague-Dawley rats (480-520 g, n=12) were used in this study. Kainic acid (3[mu]g) was stereotaxically injected through a craniotomy (10x9 mm) in the right sensorimotor cortex to produce experimental neocortical seizures. The cooling device was placed over the dura-arachnoid and a constant current (1A) was applied from a power supply. We investigated the EEG and the temperature on the cortex, and analyzed changes in amplitude of epileptiform discharges before and during cooling. We also investigated the histological changes of the cortex with Klüver-Barrera[apos]s staining after cooling. The temperature of the cortex decreased from 36.0[plusmn]0.4[ordm]C (mean[plusmn]SE) to 23.0[plusmn]1.0[ordm]C within 30 seconds after cooling. The mean amplitudes of epileptiform discharges were suppressed to 79.6[plusmn]6.2%(mean[plusmn]SE, p=0.7) and 72.5[plusmn]5.8% (p[lt]0.01) in 1 and 2 minutes after cooling, respectively. A statistically significant decrease of the amplitude was observed in slower components ([lt]8Hz) of epileptiform discharges. Histologically, there were no obvious changes in the cortex after cooling. We demonstrated the efficiency of our cooling device with Peltier chip on the suppression of experimental epileptiform activities. This device may contribute to the development of functional mapping systems or implant automatic seizure termination systems. (Supported by The Ministry of Education, Culture, Sports, Science and Technology of Japan, Grand-in-Aid for Scientific Research (C) (No.15591527))