[Influence of destruction of bilateral hippocampus upon amygdaloid kindling in rats]

It is well known that hippocampus has an important role in the development of limbic seizures in the experimental model of epilepsy. Intrahippocampal microinjections of the ibotenic acid (IBO) resulted in various degree of hippocampal degenerations and influences of these lesion upon amygdaloid kindling rats. A stereotaxic operation was carried out and bipolar electrodes were placed unilaterally in amygdala and hippocampus. The IBO solutions were injected bilaterally into dorsal hippocampus (DH) in Group A, into ventral hippocampus (VH) in Group B and into DH and VH in Group C. Phosphate buffer solutions were injected in Group D as a control. All rats were subjected to amygdaloid kindling more than 8 days after the operation. Group A, Group B, Group C, and Group D (controls) required 10.3 +/- 2.6, 11.3 +/- 2.6, 17.4 +/- 4.4 and 8.7 +/- 2.3 stimulations for the Stage V seizures, respectively. The kindling rate in Group C increased compared with controls and this increase was statistically significant (P less than 0.01). A histopathological study revealed remarkable degenerative changes in DH of Group A, in VH of Group B and all over the hippocampus in Group C. The result suggested facilitatory interaction of the hippocampus upon amygdaloid kindling.