Modulation of insulin secretion by the autonomic nervous system1

Abstract

Control of insulin secretion by the sympathetic and parasympathetic branches of the autonomie nervous system as a function of both neural input magnitude and glucose concentration was assessed. Theoretical studies using a mathematical model of insulin secretion and experimental measurements of insulin secretion from rat pancreatic islets exposed to norepinephrine and/or acetylcholine were performed. Computer simulations suggested that simultaneous exposure of the pancreas to sympathetic and parasympathetic inputs resulted in enhanced, inhibited or unchanged insulin secretion depending on the absolute and relative magnitudes of the neural inputs and the glucose concentration. Experimental conditions for sympathetic dominance (net inhibition) at 10 mM glucose were defined by computer simulation and were experimentally verified. Thus, autonomie neural control of insulin secretion is a complex function of glucose concentration and the absolute and relative magnitudes of the neural inputs applied to the pancreas. Therefore, the autonomic nervous system has the potential to regulate the amount of insulin secreted in response to glucose and, hence, food intake and body weight in a very subtle manner.