Studies on benzodiazepine receptor subtypes in a model of chronic spontaneous petit mal-like seizures.

Among the large variety of epilepsy models, differences in binding parameters on benzodiazepine (BZD) receptors could be demonstrated in some of them. A new model of petit mal-like seizures occurring spontaneously has been described in a strain of Wistar rats. The purpose of this study was to investigate the binding parameters on 'central' type and 'peripheral' type BZD receptor sites in epileptic and non-epileptic animals of this strain. Thus, using [3H]flunitrazepam as ligand, no modification was observed for 'central' type BZD sites in cortex, cerebellum and hippocampus. Nevertheless, using [3H]Ro 5-4864 as ligand, an important increase (125-150%) in the affinity constant on 'peripheral' type BZD sites was observed in epileptic rats, namely a lower affinity for the ligand on this receptor. Finally, no change occurred in the ratio between 'central' and 'peripheral' BZD receptor site apparent numbers.