Neurohormonal mechanisms that control gastrointestinal function are investigated in the following three subprojects: (1) The neural pathways of two new gastric reflexes which we recently described, the pyloro-oxyntic reflex and the oxynto-pyloric reflex, will be studied. The aim is to determine whether these reflexes are local or long (vago-vagal) by studies in which appropriate selective denervations are done. (2) An antral neurohormonal inhibitory mechanism, evidence for which was found during experiments on the pyloro-oxyntic reflex, will be studied. The aim is, as the first step towards isolating the inhibitor hormone, to determine its source (antrum, other intra-abdominal organs, or extra-abdominal site such as pituitary. (3) Search will be made for possible new neural mechanisms that integrate gastric, enteric, pancreatic and gallbladder response. The specific aim is to attempt to identify pyloro-pancreatic, pyloro-cholecystic, entero-pancreatic and entero-cholecystic reflexes. BIBLIOGRAPHIC REFERENCES: Dockray, G.J., Debas, H.T., Walsh, J.H., Grossman, M.I.: Molecular forms of gastrin in antral mucosa and serum of dogs. Proceedings of the Society of Exper. Biol. Med. 149:550-553, 1975.