NUTRIENT INGESTION INCREASES RECTAL SENSITIVITY IN HUMANS

To determine the effect of nutrient ingestion on rectal perception thr esholds (first sensation, consistent urge to defecate, pain), rectosig moid balloon distentions were performed with a computerized automated pump in eight healthy volunteers (four males, four females, 31.6 +/- 6 .02 years). Two measurements of rectal balloon distention were perform ed on 2 separate days. Day 1 served as a control condition with no mea l. On day 2 the subjects received a 600 kcal liquid meal. On the contr ol day, determination of perception thresholds was performed two times with a 10-min break between measurements. On the experimental day, th reshold determinations were made before and after the ingestion of the liquid standard meal. The order of the experimental days was counterb alanced. Distention volumes at the urge to defecate and the pain thres hold (maximum tolerable volume) were significantly reduced following t he meal. The average change from pre- to postprandial measurements of the threshold for urge to defecate was -20.55 +/- 4.22% and for the ma ximum tolerable volume it was -16.09 +/- 4.4%. These results extend da ta previously reported from animal studies using similar experimental methods.