Immunocytochemical localization of ACTH1-39 in the brainstem of the rat

The immunocytochemical distribution of ACTH1-39 (adrenocorticotropin hormone), a member of the opiocortin family of peptides, was examined in the brainstem of the rat. Immunoreactive ACTH fibers were localized in many serotonin-containing raphe nuclei and in the norepinephrine- and dopamine-containing regions throughout the brainstem. Brainstem areas involved in pain mediation contained immunoreactive ACTH fibers as well as several cranial nerve nuclei and nuclei associated with cardiovascular and respiratory functions.