[Quantitative receptor autoradiography].
The quantitative receptor autoradiographic method has been developed to determine the precise location and kinetic properties of receptors for biologically active transmitters, based on the original technique for benzodiazepine receptors in the rat brain with a 3H-labeled ligand. The autoradiography with hyperfilm-3H of cryostat sections (10- to 20-microns thick) incubated with appropriate 3H- or 125I-labeled ligands and analysis of the autoradiogram by computerized microdensitometry makes feasible quantitative determinations and complete characterization of receptors in tissues from a single animal and in human tissues obtained at autopsy. Furthermore, the autoradiographic technique has advantages over receptor binding assays with partially purified membrane preparations because it enables precise anatomical localization and has high sensitivity. In some cases, the autoradiogram can be quantitated with a computerized radioluminographic imaging-plate system. Special care has to be taken when a 3H-labeled ligand is used, since tissue quenching of the radioisotope energy of 3H is linked to the failure to attain precise quantitation of receptors in myelin-rich areas such as brain white matter. In combination with quantitative radioimmunohistochemical and in situ hybridization techniques, the quantitative receptor autoradiographic method should enable investigators to elucidate the roles of receptors for biologically active transmitters.
Niwa
M
M
Department of Pharmacology 2, Nagasaki University School of Medicine, Japan.
D000818:Animals; D001345:Autoradiography / Q000379:methods*; D006801:Humans