Imaging of human brain lesions with an ω3 site radioligand

Abstract

The topography and magnitude of increase in peripheral type benzodiazepine binding sites (ω₃ sites) was investigated autoradiographically in the brains of patients with ischemic cerebrovascular disease, with multiple sclerosis, and withj malignant glioma.³H‐PK 11195, a selective ω₃ site ligand, was employed. A manyfold increase in ω₃ site density was observed in all these disease states; this increase reflects macrophage invasion or glial proliferation or both as demonstrated by neuropathological studies carried out in parallel. There was an excellent spatial correlation between increased ω₃ site densities and extent of the lesion histologically. Specifically, an elevated density of ω₃ sites was observed in the plaques of demyelination in multiple sclerosis patients, in the periphery of infarcted zones in stroke patients, and throughout tumor in patients with grade IV astrocytomas. As our approach is applicable to both tomographic (in vivo) and autoradiographic investigations, imaging of ω₃ sites may be considered for the detection and monitoring of the natural evolution of many disorders of the human central nervous system.