Intra-amygdala all-trans retinoic acid inhibits amygdala-kindled seizures in rats

Amygdala plays an important role in induction and control of limbic seizures. There is a network of gap junctional communications in basolateral amygdala (BLA) as well. We compared the effect of intra-BLA infusion of the typical gap junction (GJ) blocker carbenoxolone (CBX), with the effect of putative GJ blocker all-trans retinoic acid (ATRA), on the afterdischarge (AD) recorded from BLA in amygdala-kindled rats. Both CBX and ATRA showed a rapid anti-seizure effect. Conversely, intra-BLA infusion of the known GJ opener, trimethylamine (TMA), enhanced seizure susceptibility by prolonging the duration of AD and generalized behavioral seizures. ATRA administered intra-BLA prevented the proconvulsant effect of TMA. The reduction of gap junctional conductance might be involved in the observed anticonvulsant effect of ATRA.