DECREASE IN [H-3] HEMICHOLINIUM BINDING TO HIGH-AFFINITY CHOLINE UPTAKE SITES IN DEAFFERENTED STRIATUM - RESTORATION BY OXIRACETAM

Frontal cortical deafferentation of the rat striatum reduces the tone of striatal cholinergic neurons. We used biochemical and autoradiographic techniques to investigate whether the [3H]hemicholonium-3 ([3H]HCh-3) binding to sodium-dependent high-affinity choline uptake sites was influenced by this lesion. Frontal deafferentation produced a reduction of about 30% in the number of [3H]HCh-3 binding sites (Brmmax) in striatum, with no significant changes in the binding affinity (Kd). Autoradiography showed a significant reduction of [3H]HCh-3 binding sites in the anteromedial portion of the striatum, but not in the posterior part of frontal deaffetented rats. Oxiracetam (100 mg/kg), a nootropic drug, did not affect the distribution of [3H]HCh-3 binding sites in sham-operated rats but completely overcame the reduction in the number of [3H]HCh-3 binding sites in deafferented striatum. © 1990.