[Expression of α(5) subunit of extrasynaptic GABA(A) receptor in insular-kindled rats].

OBJECTIVE: To explore the expression of α(5) subunit of extrasynaptic GABA(A) receptor in insular electrical kindled rats and analyze its significance. METHODS: A total of 96 male Sprague-Dawley rats were divided randomly into kindled, sham-operated and control groups (n = 32). And each group was further divided into 2 sub-groups at different time points. Kindled group: insular electrical kindled via chronic electrical stimulation; Sham-operated group: electrode implantation without electrical stimulation; CONTROL GROUP: no operation at all. The number of hippocampal neurons was detected by Nissl staining; the mRNA of α(5) subunit of hippocampus by quantitative-polymerase chain reaction (q-PCR); the expression of α(5) subunit of hippocampus by immunohistochemistry. RESULTS: No significant difference existed in the number of hippocampal neurons between epileptic and normal rats (P > 0.05). The mRNA levels of α(5) subunit of hippocampus in the sham-operated and control groups were much higher than that of the kindled group at Day 1 and 7 post-sacrificing (P < 0.01). And the hippocampal expressions of α(5) subunit were much more in the sham-operated and control groups than that of the kindled group at Day 1 and 7 post-sacrificing (P < 0.01). CONCLUSION: The hippocampal expression of α(5) subunit decreases markedly in insular epilepsy. And α(5) subunit may play an important role in the occurrence and development of insular epilepsy.