ATROPINE INHIBITS THE INCREASE IN GASTRIC-EMPTYING DURING HYPOGLYCEMIA IN HUMANS

OBJECTIVE - To study the effect of a cholinergic muscarinic blockade on the gastric emptying rate during insulin-induced hypoglycemia in healthy subjects. RESEARCH DESIGN END METHODS - In eight healthy subjects, the rate of gastric emptying of an isotope-labeled meal was assessed by a scintigraphic technique during normoglycemia and hypoglycemia with simultaneous infusion of either atropine or saline. Blood glucose concentrations were controlled by an insulin-glucose clamp. RESULTS - The median lime for emptying 50% of the liquid phase from the stomach (T-50) was 24.9 min (range 13.9-120.0) during normoglycemia compared with 8.1 min (range 3.6-16.5) during hypoglycemia without atropine infusion (P = 0.0005). The T-50 for the solid phase was 26.8 min (range 9.7-74.0) and 43.1 min (range 29-57.8), respectively (P = 0.007). During hypoglycemia with atropine infusion, T-50 was 40.7 min (range 10.0-120.0) for the liquid phase and 111.4 min (range 38.9-120.0) for the solid phase, not statistically different from normoglycemic examinations. CONCLUSIONS - Cholinergic muscarinic blockade with atropine inhibits the increase in gastric emptying during hypoglycemia. Vagal activity seems to be an important determinant of gastric emptying during hypoglycemia.