Changes in purine levels and adenosine receptors in kindled seizures in the rat

Adenosine is an inhibitory modulator of neuronal activity and its possible involvement in seizures is of interest. We have examined changes in adenosine, its metabolites and receptors in brains of hipppocampus-kindled rats, a model of partial epilepsy. Purine levels were measured by in vim microdialysis and showed a small increase in adenosine and a dramatic increase in its metabolites after kindled seizures. Adenosine A(I) receptor binding using [H-3]DPCPX was unaltered after seizures, whereas A(I) agonist stimulated binding of GTP[gamma-S-35] and A(I) mRNA expression increased in the CA3 and other regions. Striatal adenosine A(2A) mRNA and receptor binding with [H-3]SCH-58261 decreased. These findings indicate that kindled seizures increase adenosine release and metabolism and induces adaptive changes in adenosine receptors.