Alterations in [3H]desmethylimipramine binding in the aged rat brain: an in vitro autoradiographic demonstration

Using in vitro autoradiographic receptor binding, the present report provides a descriptive analysis of [3H]desmethylimipramine ([3H]DMI) binding in the aged rat brain. Small circular patches of intense [3H]DMI binding were present within the caudate nucleus in every aged brain examined. Occasionally, similar patches of label were present in restricted cortical regions of aged brains. Comparable patches of [3H]DMI binding were never observed in young brains used in these investigations. Additional evidence suggests that these age-dependent changes in [3H]DMI binding are anatomically restricted to the loci indicated above.