Further evidence for the subsensitivity of striatal AMPA receptors, induced by chronic haloperidol administration: an autoradiographic study

The aim of the present study was to investigate the influence of chronic treatment with haloperidol on the striatal N-methyl-D-aspartate (NMDA), -amino-3-hydro-xy-5-methyl-4-isoxasole-propionic acid (AMPA) and dopamine D₂ receptors using a quantitative autoradiography in rats. Haloperidol was given to animals in a dose of ca. 1 mg/kg/day in drinking water for 6 weeks or 3 months and was afterwards withdrawn for 5 days. Haloperidol increased by 20–50% the binding of [³H]spiperone in different regions of the caudate-putamen. Haloperidol decreased by ca. 30% the binding of [³H]AMPA in the ventrolateral region of intermediate part of the caudate-putamen, but did not influence the binding of [³H]MK-801. The present results suggest that, apart from supersensitivity to dopamine, chronic treatment with haloperidol also induces subsensitivity of striatal AMPA receptors.