Changes in GABA(A) receptor alpha(1) subunit gene expression occur in the globus pallidus and substantia nigra pars reticulata following lesions of the nigrostriatal tract. To determine whether these changes are translated at the protein level, we performed quantitative autoradiography with the alpha(1) selective ligand, [H-3]zolpidem, and the non-selective benzodiazepine site ligand, [H-3]Ro 15-1788. Binding of both [H-3]zolpidem and [H-3]Ro 15-1788 was significantly increased in the substantia nigra pars reticulata (13.5+/-4.1 and 26.3+/-2.9%, respectively) and significantly reduced in the globus pallidus (20.9+/-0.8 and 18.3+/-1.3%, respectively). These changes in alpha(1) subunit protein expression may help to compensate for the pathological changes in GABAergic activity that occur after striatal dopamine depletion. (C) 2000 Elsevier Science B.V. All rights reserved.