Abstracts

RATIONALE:Mice are available for gene-targeting study and easy to handle. However because their skull are small, there are difficulties for recording and stimulations. We investigated whether stages of amygdala kindling in mice are the same as in other species and whether there is secondary epileptogenesis. METHODS:Electrodes were constructed of enamel coated stainless steel wire, linked with silver wire and soldered to a miniature connector. Administration of 30 mg/kg pentobarbital was followed by the implantation of the electrodes bilaterally into the basolateral amygdala in C57BL/6J mice at the coordinates (B-2.0, L3.0, H-4.5) using the stereotaxic technique. Once-daily stimulation of biphasic square pulse (1msec, 60 Hz, 100 A, 2 sec) was applied through the stimulation electrode. Electrographic records were obtained and filed using EEG recorder. RESULTS:The behavioral changes of the kindling in mice were: 1)arrest of behavior, 2)head nodding, 3)forelimb clonus,4) both forelimbs clonus with rearing, 5) tonic generalized convulsion, falling with GTC, sometimes jumping and myoclonus followed. Eleven stimulations were required for the full kindling. Afterdischarges became longer following kindling. Spontaneous epileptiform potentials at the stimulation place appeared after the 8th stimulation. In addition, synchronous epileptiform potential appeared on the contralateral amygdala. After more than 11 stimulations independent epileptiform potentials appeared on the secondary site. CONCLUSIONS: The behavioral change of mice kindling was relatively similar to the rat kindling. However there were small differences such as the early synchronous clonus of both forelimbs and myoclonus. And there were independent spontaneous epileptiform potentials on the secondary site. This presentation will be the first on the secondary epileptogenesis in mice.