Amygdala adenosine A(1) receptors have no anticonvulsant effect on piriform cortex-kindled seizures in rat

Abstract

Adenosine is an endogenous anticonvulsant that exerts its effects through A(1) receptors. As the piriform/amygdala is a critical circuit for limbic seizure propagation, in this study, the role of basolateral amygdala A(1) receptors on piriform cortex (PC)-kindled seizures was investigated. Rats were kindled by daily electrical stimulation of PC. In fully kindled animals, bilateral intra-amygdala N-6-cyclohexyladenosine (CHA; 10-500 mu mol/L, a selective A(1) receptor agonist) had no effect on kindled-seizure parameters. However, bilateral intra-amygdala 2% lidocaine (reversal neuronal inhibitor) reduced the kindled seizure severity. There was significant increase in stage 4 latency and decrease in stage 5 duration. Bilateral lesion of basolateral amygdala of kindled animals (by electrical DC current) reduced the kindled seizure severity more dramatically. Our results showed afterdischarge duration, stage 5 duration, and seizure duration were decreased and stage 4 latency increased significantly. In addition, daily intra-amygdala CHA had no significant effect on PC kindling acquisition. Therefore, it may be concluded that although the basolateral amygdala neuronal activity has a critical role in the propagation of epileptic seizures from PC, the amygdala A(1) receptors have no role in this regard. On the other hand, amygdala A(1) receptors have no anticonvulsant or antiepileptogenic effect on PC-kindled seizures.