Neuropeptide Y-like immunoreactive structures in the rat stomach with special reference to the noradrenaline neuron system.

The origins and overall distribution of neuropeptide Y-like immunoreactive (NPYI) structures in the rat stomach were investigated by immunofluorescent staining of muscle strips from rats subjected to chemical and surgical neurotomy. The present study has demonstrated that the majority of NPYI fibers in the myenteric plexus and along the blood vessels in the muscle layers originate from NPYI cell bodies located in the celiac ganglion, which also contains noradrenaline. The remaining NPYI fibers in the circular and longitudinal muscle layer and a small number of NPYI fibers in the myenteric plexus do not contain noradrenaline and are of intrinsic origin. Noradrenaline fibers in the muscle layer are not associated with blood vessels. They originate from the celiac ganglion but do not contain NPYI structures.