Effect of acute exercise at different intensities after food intake on gastric emptying in rats

To investigate the effect of acute running exercise on gastric emptying, changes in gastric contents remaining, plasma levels of adrenaline, noradrenaline, gastrin, and cholecystokinin (CCK) in response to exercises of different intensities were examined in rats. After fasting for 18 hours, the rats were divided into two running groups and a control group, and fed test meal containing 37kBq/g of indium-114m at 1g/100g body weight. Fifteen minutes after test meal feeding, each of the rat ran on a rodent treadmill at the speed of 15m/min (L:n=8), 35m/min (H: n=8), or stayed on the treadmill without running (C:n=8) for 30 minutes, respectively. Blood, stomach, and small intestine were sampled immediately after the end of running or staying. The plasma level of noradrenaline in H was significantly higher than that in L (p<0.01). The plasma level of adrenaline in H was significantly higher than those in C (p<0.05) and L (p<0.01). The plasma level of gastrin in H was significantly lower than those in C (p<0.01) and L (p<0.01), and that in L was significantly lower than in C (p<0.05). The plasma level of CCK in L was significantly higher than those in C (p<0.05) and H (p<0.01). The % gastric contents remaining in H was significantly higher than those in C (p<0.01) and L (p<0.05), and that in L was significantly higher than in C (p<0.05). These results suggest that the low intensity exercise suppresses a function of gastric emptying by increasing plasma CCK, and that an increase in intensity of exercise enhance the suppressive effect on the function of it by increasing adrenergic nerve activity in rats.