Opiate receptor: autoradiographic localization in rat brain.

Opiate receptor sites in rat brain can be labeled in vivo by [3H]diprenorphine, a potent opiate antagoinst. Using techniques to minimize diffusion in fresh, frozen, unfixed brain, we have localized [3H]diprenorphine by autoradiography to visualize the distribution of opiate receptors. Silver grains indicative of the binding of labeled [3H]diprenorphine are discretely localized in numerous areas of the brain with very high densities in the locus coeruleus, the substantia gelatinosa of the spinal cord, and in clusters within the caudate-putamen, amygdala, and parts of the periventricular gray matter.