Autoradiographic localization of [3H]nicotine binding sites in the rat brain.

In vitro autoradiography was used to visualize [3H]nicotine binding sites in the rat brain. Labeling was densest in the interpeduncular nucleus and medial habenula but was also detected in thalamic nuclei, areas related to sensory function, the cerebral cortex, and molecular layer of the dentate gyrus. Specific binding was sparse in the hypothalamus and caudate-putamen, and not detected in Ammon's horn of the hippocampus or in the periaqueductal grey matter. These findings may relate to the distribution of nicotine's cerebral loci of action.