[3H] Quinuclidinyl Benzylate and [3H] GABA Receptor Binding in Rat Substantia Nigra After 6-hydroxy-dopamine Lesions

6-Hydroxydopamine lesions of the nigrostriatal DA pathway resulted in a 30% reduction (P less than 0.01) of nigral [3H] quinuclidinyl benzylate (QNB) binding at 3 weeks after lesion and this reduction in binding was characterised by a loss of [3H] QNB binding sites with no change in affinity. The binding of [3H] GABA to Triton-treated membranes was 12% lower (non-significant) in the nigrae of the lesioned than of the non-lesioned hemisphere, but was not characterised further. The results suggest the location of muscarinic ACh receptors on the cell bodies or dendrites of nigral DA neurons.