Expression of gap junction connexin 32 and connexin 43 and inhibition of carbenoxolone in cultured hippocampal neurons of rats after epileptiform discharges

Objective To study the role of gap junctions in epileptiform activity. Methods The epileptiform activity was induced by zero-Mg 2+ medium in cultured hippocampal neurons of newborn rats. Immunocytochemistry and real time RT-PCR were introduced to evaluate the expression of gap junction Cx32 and Cx43. Results The level of Cx32 mRNA increased quickly one hour after the neurons were treated with zero-Mg 2+ medium and was raised by 10 times 5 hours later, while Cx32 protein began to develop at the 2nd hour (21.80±1.74) and was raised by 5 times at the 8th hour (47.30±5.75). The expression of Cx43 mRNA went up obviously 5 hours later, and Cx43 protein developed visibly 8 hours later. Carbenoxolone depressed the expressions of Cx32 and Cx43. Conclusions The expression of Cx32 and Cx43 increases dramatically after epileptic discharges and carbenoxolone inhibits both the discharges and the expression of gap junctions, which indicates that gap junction could contribute to epileptogenesis.