Binding of RO 5–4864 To Brain Membranes of Rats with and Without Absence-Like Phenomena

Abstract

Spontaneously occurring spike-wave discharges (SWD) in rats are used as a model for absence epilepsy in humans. In vitro, the binding parameters of ³H-Ro 5–4864, a ligand labelling the peripheral benzodiazepine receptor, were determined for brain membranes of WAG/Rij rats, an inbred strain showing SWD, and for ACI rats, an inbred strain showing no SWD. No difference in the K_d but a small difference in the B_max values between the strains were found. Recently, other investigators reported a correlation between a decrease in affinity for ³H-Ro 5–4864 and the occurrence of SWD. Our results suggest however that it is doubtful that a change in K_d of the peripheral benzodiazepine receptor is causal in the etio-pathology of the spontaneous absence like phenomena in rats.