[Importance of the cholinergic nervous system in the postprandial secretion of insulin in dogs].

This work was designed to study the evolution of blood glucose and plasma insulin after food intake. The experiments were performed on normal conscious dogs. Blood was sampled from the jugular vein. The animals had a meal consisting of meat (30 g/kg) or received a nutrient undergoing direct resorption, glucose (1 g/kg). 10 minutes before the intake of meal or glucose, some animals received an i.v. injection of atropine (0.2 mg/kg). The ingestion of meat did not change blood glucose level, but induced a biphasic increase in insulin secretion, the second phase persisted at least for 240 minutes. The previous injection of atropine totally suppressed the increase in insulinemia. The oral intake of glucose induced hyperglycemia and a biphasic increase in insulinemia. The injection of atropine suppressed the first phase of hyperinsulinemia; then the increase of insulinemia evolved in parallel to hyperglycemia. These results, observed in the dog, underline the importance of the cholinergic nervous system not only during the early phase of insulin secretion (cephalic phase), but also during a prolonged post-prandial period.