Regional differences in NaCl-induced increase of the potency of bicuculline to displace [3H]muscimol binding.

It has been shown that the potency of bicuculline to displace [3H]muscimol binding to crude brain membranes can be enhanced markedly by different anions. This study shows that although bicuculline alone was a more potent displacer of [3H]muscimol binding in cortical than in cerebellar membranes, the NaCl (250 mM)-induced leftward shift of the bicuculline inhibition curve of [3H]muscimol binding was considerably higher in cerebellum than in cortex. The some concentration of NaCl failed to affect either the affinity or the density of cortical and cerebellar [3H]muscimol binding sites. The results suggest that sodium chloride is able to reveal regional differences in bicuculline potency.