Intraperitoneal and intraamygdala N(6)-cyclohexyladenosine suppress hippocampal kindled seizures in rats.

Effects of intraperitoneal and intraamygdala N(6)-cyclohexyladenosine (CHA), a selective adenosine A(1) receptor agonist, and 1,3-dimethyl-8-cyclopentylxanthine (CPT), a selective adenosine A(1) receptor antagonist, were examined in fully hippocampal kindled rats. Intraperitoneal administration of CHA (0. 25, 0.5 and 1 mg/kg) decreased hippocampal secondary afterdischarge duration (SAD) and amygdala afterdischarge duration (ADD). Only the 1 mg/kg dose induced a significant increase in latency to stage 4. Intraperitoneal administration of CPT (0.25, 0.5 and 1 mg/kg) induced a significant increase in stage 5 duration, hippocampal SAD and ADD. Pretreatment of animals with CPT (1 mg/kg), antagonized effects of CHA on seizure parameters. Intraamygdala microinfusion (1 microl over 2 min) of CHA (5 nM-1 mM) significantly reduced hippocampal SAD and amygdala ADD. These effects were antagonized by intraamygdala CPT (1 microM). Results obtained suggest that in hippocampal kindled rats, amygdala may be regarded as a relay point for AD propagation specially in recruit activity of the hippocampus.