GASTRIC BRANCH VAGOTOMY AND GASTRIC-EMPTYING DURING AND AFTER INTRAGASTRIC INFUSION OF GLUCOSE

The effect of gastric branch vagotomy (GVX) on the gastric emptying of glucose was evaluated during two phases of emptying control: as the s tomach fills and in the postload period. GVX and control rats received a series of intragastric glucose infusions (1.0 ml/min) through indwe lling gastric fistulas. In experiment 1, gastric samples were withdraw n either immediately after the offset of 9- or 18-min infusions of 12. 5% glucose or at various times up to 36 min postinfusion. In experimen t 2, samples were withdrawn either immediately or 30 min after termina tion of 12-min infusions of 12.5 or 25% glucose. After gastric fill, g lucose solute emptying rate was stable over time, not influenced by co ncentration doubling, and, surprisingly, not affected by GVX During ga stric fill, solute emptying rate doubled with concentration in both GV X and control rats. For each concentration, however glucose emptied du ring fill at almost twice the rate in GVX compared with control rats. This accelerated emptying of glucose during fill in GVX rats is consis tent with a gastric vagal contribution to inhibitory mechanisms (e.g., receptive relaxation) that operate as the stomach fills under normal conditions. The absence of a GVX effect on emptying after fill suggest s either that gastric branch vagal efferents play little role in feedb ack inhibitory control of glucose emptying under normal conditions or that other systems compensate for the function previously served by va gal gastric branch efferents. Further work is required to address the possible role of the gastric vagus in feedback control of gastric empt ying when nutritive fluids other than glucose are delivered.