Caudal raphe-dorsal vagal complex peptidergic projections: Role in gastric vagal control

Abstract Subpopulations of raphe pallidus (Rpa) and raphe obscurus (Rob) neurons containing TRH, serotonin (5-HT), and substance P contribute projections to the dorsal vagal complex (DVC). Activation of Rpa and Rob neurons induces a vagal cholinergic-dependent stimulation of gastric secretory and motor function and modulates resistance of the gastric mucosa to gastric injury in rats and cats. The caudal raphe nuclei-DVC pathways containing TRH/5-HT are involved in mediating cold-induced vagal stimulation of gastric function and erosion formation. These results suggest that Rpa/Rob-DVC projections containing TRH/5-HT may be an important pathways in the medullary regulation of vagal activity to the viscera.