Anticonvulsant effects of intrahippocacampal N6-cyclohexyladenosine on piriform cortex-kindled seizures

In this study the role of adenosine A1 receptors of the CA1 region of hippocampus on piriform cortex–kindled seizures was investigated in rats. Obtained results showed that in kindled animals, bilateral microinjection of N6–cyclohexyladenosine (CHA), an adenosine A1 receptor agonist, at doses of 10 and 100 mM into the hippocampal CA1 region decreased the afterdischarge duration (ADD), stage 5 seizure duration (S5D) and seizure duration (SD), and increased the latency to stage 4 (S4L) significantly. CHA at the doses of 1 mM decreased only ADD and no changes were observed at the doses of 0.1 mM. Bilateral microinjection of 1,3-dimethyl-8-cyclopenthylxanthine (CPT), an adenosine A1 receptor antagonist, into the CA1 region of hippocampus increased ADD at the dose of 20 mM significantly, but has no effect on seizure parameters at the dose of 10 mM. Pretreatment of animals with CPT (10 mM) before CHA (10 and 100 mM), reduced the effect of CHA on seizure parameters significantly. Thus, it may be suggested that the hippocampal CA1 region may play a role in relaying or spreading of seizure spikes elicited from the piriform cortex, and activation of adenosine A1 receptors of this region can prevent this actions.