The role of adenosine A1 receptors on post seizure depression period in rats

Epilepsy is among the most common disorders of the central nervous system and there is not an absolute method for its treatment. It has been shown that each seizure has a depressing effect on the following seizure. Thus, finding the mechanisms responsible in this phenomenon can improve our knowledge toward new ways for epilepsy treatment. In this study, the role of adenosine A1 receptors in post seizure depressing period was investigated in amygdala kindling model of epilepsy. Methods: Rats were kindled by daily electrical stimulation of amygdala. At first, different groups of kindled animals were stimulated at different times after the first stimulation and the percent of suppression of seizure parameters were calculated. Then, 8-cyclopenthyl-1, 3-dimethylxanthine (CPT), a selective adenosine A1 receptor antagonist (50 and 200 μM) were intracerebroventricularly microinjected before the second stimulation and its effect on percent of suppression induced by the first stimulation was investigated. Results: In the second stimulation, applied at 10 and 30 min after the first stimulation, the seizure parameters were significantly reduced. CPT microinjection (50 and 200 μM) significantly decreased the percent of suppression of seizure parameters. This decrease was significant at 10 and 30 min after the first stimulation with compare to the groups received the drug solvent. Conclusion: Obtained results showed that endogenous adenosine has a role in post seizure depression period through A1 receptors. As the blocking of A1 receptors by CPT could not completely prevent this period, other factors may also play role in this suppression.