We propose to study various aspects of pancreatic neuroendocrinology. By perfusing the innervated, but otherwise isolated, pancreas of a small dog (c. 3 kg) with blood from a large dog (c. 30 kg), it is possible to separate neural stimuli of the organ from blood borne activators and inhibitors. Using this preparation, direct electrical stimulation of the vagi enhances, while a similar stimulus delivered to the splanchnic nerves inhibits, the insulin secretion rate. We are now investigating the location and sensitivity of the afferent limbs of reflex arcs which may relay signals from various parts of the small dog to its pancreas. BIBLIOGRAPHIC REFERENCES: Neural Inhibition of Insulin Secretion from the Isolated Canine Pancreas. Ralph E. Miller. Fed. Proc. 34: 254, 1975; Neurally Mediated Alteration of Insulin Secretion by Endogenous Stimuli. Thomas H. Waid, M. Patricia Joyce, and Ralph E. Miller. Diabetes 24, Supplement 2: 403, 1975. Presented at the 1975 American Diabetes Association Annual Meeting. (Abstract of presentation).