chapter  4
24 Pages

Organization of CRF Immunoreactive Cells and Fibers in the Rat Brain: Immunohistochemical Studies

ByP. E. Sawchenko, L. W. Swanson

This chapter provides an update on the central distribution of corticotropin releasing factor (CRF)-immunoreactive (CRFir) from a systems-level perspective. It summarizes what is known about the anatomic organization of CRF in particular systems and pathways. At the ultrastructural level, CRF-stained neurons in the parvocellular division of the paraventricular nucleus of the hypothalamus have been described that display morphologic specializations typical of neurosecretory neurons. CRF has been localized within terminals in the external lamina of the median eminence, where staining is associated with secretory vesicles. The course of CRFir fibers to the median eminence has been studied in normal immunohistochemical material and using combined ablation-immunohistochemical approaches. The preponderance of localizations in central neuroendocrine- and autonomic-related systems described in initial surveys of CRFir in the rat brain provided a basis for suggesting that the central CRF system might function in a unitary manner to orchestrate endocrine, autonomic, and behavioral responses to stress.