Splanchnic neural regulation of insulin and glucagon secretion in the isolated perfused human pancreas

The isolated perfused human pancreas was employed as a model in which electrical stimulation of the celiac mixed neural bundle was performed in the presence or absence of selective neural blockers. The insulin and glucagon responses to hyperglycemia alone or in the presence of splanchnic nerve stimulation were similar in magnitude to the results obtained in a preliminary report on isolated human pancreatic function and in studies using animal models. Stimulation of the celiac neural bundle in the presence of hyperglycemia resulted in an inhibition of insulin release and in an augmentation of glucagon release. α-adrenergic stimulation resulted in a strong suppression of insulin secretion and a mild suppression of glucagon secretion. β-adrenergic fiber stimulation caused a mild augmentation of both insulin and glucagon release, whereas the cholinergic fibers strongly stimulated both alpha- and beta-cell secretion. The predominant effects of celiac neural bundle stimulation are insulin inhibition by way of an αadrenergic effect and glucagon stimulation by way of a cholinergic effect. Thus, in this in vitro human model, our data confirm that the splanchnic innervation of the pancreas has a potent regulatory role on pancreatic hormone release in human subjects.