GABAA sodium independent receptor sites in a strain of rats presenting generalized non-convulsive seizures

The role of gamma-aminobutyric acid (GABA), a major inhibitor neurotransmitter in the central nervous system (CNS), is well established in the genesis and the control of epilepsies. The purpose of this work was to study the binding parameters of the Na(+)-independent GABA receptors in the brain of a strain of rats presenting spontaneous generalized non-convulsive seizures. The high- and low-affinity binding sites were evaluated in cerebral cortex, cerebellum, and hippocampus using [3H]muscimol. No significant modification was observed for the Bmax and the Kd of high-affinity binding sites, although a slight decrease of Bmax was noted in the three brain areas in rats with seizures. Concerning the low-affinity binding sites, significant decreases were observed in the values of Bmax in the cortex, cerebellum, and hippocampus of animals with spontaneous seizures, without modification of Kd values. Such changes could be considered to be involved in some of the physiological and behaviour activities observed in this strain of rats.