DIDS, an anion transport blocker, modulates ivermectin-induced enhancement of benzodiazepine receptor binding in rat brain

Ivermectin enhancement of 3H]diazepam binding was abolished by pretreatment of membranes with 0.05% Triton X-100, whereas GABA-induced enhancement was not changed after this treatment. Ivermectin enhancement was neither affected by picrotoxinin nor dependent on the chloride ion. 4,4'-Diisothiocyano-2,2'-disulfonic acid stilbene (DIDS) dose-dependently reduced 3H]diazepam binding enhanced by 10(-6) M ivermectin, without affecting the basal specific binding. The effects of DIDS were derived from reduction of increased binding affinity of benzodiazepine receptors by ivermectin, but were not dependent on chloride ion in the assay medium. DIDS inhibited GABA- and pentobarbital- but not chloride ion-induced enhancement of 3H]diazepam binding.