VISUALIZATION OF AN EFFERENT PROJECTION ROUTE OF THE HYPOTHALAMIC RATARCUATE NUCLEUS THROUGH THE STRIA TERMINALIS AFTER LABELING WITH CARBOCYANINE DYE (DII) OR PROOPIOMELANOCORTIN-IMMUNOHISTOCHEMISTRY

The hypothalamic arcuate nucleus is known to be reciprocally connected to various limbic regions, such as the bed nucleus of the stria termi nalis (BST). The route of this reciprocal connection, in particular wi th the BST, remains unknown. In order to visualize this pathway, we us ed the fluorescent tracer carbocyanine dye (DiI), that was inserted in the arcuate nucleus in fixed and dissected brains. This allowed us to label an arcuate-BST pathway DiI-labeled coursing through the stria t erminalis. Immunohistochemistry for the arcuate-derived peptide adreno cortico-tropin (ACTH) revealed the presence of ACTH-immunoreactive axo ns in the stria terminalis. Together, these results provide arguments in favour of the existence of an arcuatofugal projection to the BST vi a the stria terminalis.