Role of insular cortex in amygdala-kindled seizures in rats

Objective To investigate the role of insular cortex in amygdala-kindled seizures in rats.Methods Forty-eight healthy male SD rats were randomly divided into blank control group (n=8),sham-operated group (n=8) and amygdala-kindled group (n=32); no treatment was performed in the blank control group,and only implantation of electrodes was performed in the sham-operated group; implantation of electrodes and electrophotoluminescence were performed in the amygdala-kindled group to induce amygdala-kindled seizure models.Rats in the amygdala-kindled group was divided into 4sub-groups (n=8) at different times after the kindling (1,3,6 and 12 h).Fluorescence in situ hybridization and immunohistochemistry staining were employed to investigate the altered mRNA and protein expressions of activity-regulated cytoskeleton-associated protein (Arc) in the hippocampus and insula of the rat brain.Results As compared with that in the blank control group and sham-operated group,Arc mRNA expression in the amygdala-kindled sub-groups increased at 1 h after the kindling (P＜0.05),peaked at 3 h after the kindling (P＜0.05),and returned to basic level at 6 h after the kindling (P＞0.05).As compared with that in the blank control group and sham-operated group,Arc protein expression in the amygdala-kindled sub-groups increased at 3 h after the kindling,(P＜0.05),peaked at 6 h after the kindling (P＜0.05),and returned to basic level at 12 h after the kindling (P＞0.05).No significant difference on mRNA and protein expressions of Arc was noted between the sham-operated group and blank control group (P＞0.05).Conclusion Insular cortex,the amygdala and the hippocampus form a focus complex,which participates in the occurrence of temporal lobe epilepsy. Key words: Insular cortex;  Amygdala;  Hippocampus;  Kindling;  Activity-regulated cytoskeleton-associated protein