Glutamate binding is altered in hippocampus and cortex of Wistar rats after pilocarpine-induced Status Epilepticus

Several evidences have pointed to biochemical alterations in some brain structures after experimental Status Epilepticus (SE). Thus, the effects of pilocarpine-induced SE on the glutamate binding in the hippocampus and cortex of Wistar rats were evaluated. Groups of animals were submitted to a 3 h SE induced by intrahippocampal microinjection of pilocarpine, which was interrupted by the administration of sodium thiopental. Two weeks later the animals were sacrificed and had their cerebral cortices and hippocampi removed in order to perform the binding experiments. The results show that the pilocarpine-induced SE provoked an increase in 2.5-fold in the Bmax values for glutamate binding in the cortex, but not in the hippocampus. Moreover, we observed a 4-fold increase for the Kd values in the hippocampus and a 2-fold increase in the cortex. These findings might indicate that the epileptogenesis involves alterations in the glutamate receptors that are not restricted to the limbic system. Moreover, changes in these receptors are not exclusively of number, but rather involve the affinity for their ligands.