Reduction of A1 adenosine receptors in rat hippocampus after kainic acid-induced limbic seizures

In a temporal lobe epilepsy (TLE) model induced by kainic acid (KA), we examined the effect of limbic seizures on Al adenosine receptor distribution in hippocampus and cortex. By using quantitative autoradiography, we determined a progressive decrease in Al receptor density in CA1 and CA3 regions of hippocampus, which coincided in time with the degenerating process of hippocampal pyramidal cells. This result indicates that a great amount of Al receptors are located postsynaptically on pyramidal cell dendrites. No difference in Al receptor density was observed in the inner compared to the outer molecular layer of dentate gyrus, or in the infrapyramidal band compared to the outer layer of stratum oriens of CA3. This could indicate that the newly sprouted mossy fiber glutamatergic terminals do not contain Al receptors, thus lacking a restrain in the release of glutamate. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.