Document Type : Original Article
Introduction: The role of adenosine A1 receptors of the entorhinal cortex on amygdaloid kindled seizures was investigated.
Material and Methods: Animals were kindled by daily electrical stimulation of amygdala. In the full kindled animals, N6-cyclohexyladenosine (CHA; 0.1, 1 and 10 mM), an adenosine A1 receptor agonist, and 8-cyclopenthyle 1,3-dimethylexanthine (CPT), an adenosine A1 receptor antagonist, at concentrations of 1 and 5mM were injected bilaterally into the entorhinal cortex. Animals were stimulated at 5, 15, 60 and 120 min post drug infusion and kindling parameters were measured.
Results: Results showed that CHA at concentration of 10 mM reduced amygdala after-discharge duration, entrorhinal cortex after-discharge duration (E-ADD) and stage 5 seizure duration at 5, 15,60 and 120 min post drug injection. It also increased the latency of stage 4 seizure. But, no alteration was observed in seizure stage. At concentrations of 1 and 0.1 mM, CHA reduced E-ADD only at 5 and 15min post drug infusion. Bilateral injection of CPT into the entorhinalcortex did not alter seizure parameters. Intra-entorhinal cortex injection of CPT (5mM), 5 min before CHA (10mM), blocked the anticonvulsant effects of CHA.
Conclusion: These results suggest that the entorhinal cortex has a role in seizure propagation from the amygdala and its adenosine A1 receptors activity have anticonvulsant effects on amygdala kindled seizures.