Immunocytochemical localization of corticotropin releasing factor (CRF) in the rat spinal cord

The presence of corticotropin releasing factor (CRF)-immunoreactive nerve fibers and cell bodies in the spinal cord is demonstrated. Immunopositive fibers were found in the lateral column of the white matter, in laminae I, V–IV, X, and in the intermediolateral column of the spinal cord. Complete transection of the spinal cord showed that the majority of the fibers in the lateral funiculus formed an ascending pathway; however, a few descending fibers were also detected. Hypophysectomy resulted in enhanced immunoreactivity to the fibers and staining of CRF-immunoreactive cell bodies in laminae V–VII, X, and in the intermediolateral sympathetic column. The results suggest that CRF is not merely an ACTH releasing factor, but also a regulatory peptide which may be involved in several stress-related neural responses.