GASTRIC PRESSURES IN PIGS DURING EATING AND DRINKING

Pressures were measured with miniature transducers positioned within t he gastric lumen of six young pigs, 20-40 kg, eating and drinking oper antly. The pigs were free to move about, lie down, sleep, eat, and dri nk without disturbance. 1) At the end of 4-5-h fasts (with no drinking ), mean pressure within the stomach was 12 cm H2O, then rose during 22 -min eating bouts to 22 cm H2O. 2) At the end of 16-18-h periods of fo od and water deprivation, intragastric pressure was 9 cm H2O. When wat er was drunk, pressures rose only to 13 cm H2O, then fell. When food w as then eaten, pressures rose during 29-min meals to 22 cm H2O. 3) Dur ing spontaneous eating and drinking, intermeal pressures were maintain ed at 22-25 cm H2O, fell by 4-5 cm H2O just as eating or drinking bega n, then rose slowly, but only to the preingestive pressure level by th e end of the bout. These results indicate that during spontaneous eati ng and drinking, gastric distention per se plays a smaller direct role in causing satiety than it does during meals ingested after a period of food deprivation.