Localization of DARPP-32 immunoreactive neurons in the bed nucleus of the stria terminalis and central nucleus of the amygdala: co-distribution with axons containing tyrosine hydroxylase, vasoactive intestinal polypeptide, and calcitonin gene-related peptide.

The distribution and morphology of neurons containing the dopamine- and cyclic AMP-regulated phosphoprotein, DARPP-32, were investigated in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (CeA). DARPP-32 immunoreactive neurons are numerous in both regions, but are restricted to the lateral dorsal and the lateral juxtacapsular subdivisions of the BST, and the central lateral and lateral capsular subdivisions of the CeA. Immunoreactive neurons in the lateral dorsal BST, and the central lateral and lateral capsular CeA are similar morphologically, while those in the juxtacapsular BST appear to be a subpopulation of striatal medium-sized spiny neurons. The distribution of DARPP-32 immunoreactive neurons in the BST and CeA overlaps considerably with axonal plexuses containing tyrosine hydroxylase (TH), vasoactive intestinal polypeptide (VIP), and calcitonin gene-related peptide (CGRP). These studies provide further evidence of the close relationship between the CeA and BST, and also provide anatomical evidence for possible interactions between neurotransmitters, neuropeptides, and phosphoproteins.