Quantitative autoradiography of neurotransmitter receptors in Huntington disease

We studied gamma-aminobutyric acid (GABA), benzodiazepine, and muscarinic cholinergic receptor-binding by quantitative autoradiography. In coronal sections from the brain of a patient with Huntington disease, binding for all three receptors in caudate and putamen was lower than control values. Binding to GABA and benzodiazepine receptors was increased in lateral and medial pallidum and decreased in ventrolateral thalamus. Muscarinic cholinergic receptors were markedly decreased in pallidum but not thalamus. The findings suggest that loss of striatal afferents to both segments of pallidum results in GABA and benzodiazepine receptor supersensitivity, and support the utility of quantitative autoradiography for receptor studies in human postmortem material.