INTESTINAL LIPID INHIBITS GASTRIC-EMPTYING VIA CCK AND A VAGAL CAPSAICIN-SENSITIVE AFFERENT PATHWAY IN RATS

The mechanism by which lipid in the duodenum inhibits gastric emptying was investigated in awake rats fitted with chronic gastric and duoden al cannulas. Perfusion of the duodenum with lipid (Intralipid, 5 and 1 0%; total amount 50 and 100 mg) caused a significant inhibition (26 an d 78%, respectively) of gastric emptying of a nonnutrient liquid (0.9% saline). Functional ablation of the capsaicin-sensitive vagal, but no t the spinal, sensory innervation to the upper gastrointestinal tract significantly attenuated by 57% lipid-induced inhibition of gastric em ptying. In intact rats, administration of a specific cholecystokinin ( CCK)-A receptor antagonist, devazepide, significantly attenuated by 66 % the response to lipid. Administration of devazepide in perivagal cap saicin-treated rats did not further reduce the response to lipid. Thes e results suggest that lipid in the duodenum inhibits gastric emptying via a mechanism involving an action of CCK at type A receptors and ca psaicin-sensitive vagal afferents.