Pituitary adenylate cyclase-activating polypeptide-like immunoreactivity in autonomic regulatory areas of the rat medulla oblongata.

Pituitary adenylate cyclase-activating polypeptide-like immunoreactivity (PACAP-LI) was mapped immunohistochemically in the rat medulla oblongata. We found the majority of perikarya with PACAP-LI in the visceral areas of the solitary nucleus, dorsal motor vagal nucleus, nucleus ambiguus, ventrolateral medulla, ventral medullary surface, and caudal raphe nuclei. Medium densities of labeled fibers were detected in the area postrema, solitary nucleus, dorsal vagal and raphe pallidus nuclei. Our morphological data support the hypothesis that PACAP is a central regulator of visceral functions.