CONTROL OF GASTRIC-EMPTYING IN THE PIG - INFLUENCE OF CHOLECYSTOKININ, SOMATOSTATIN AND PROKINETIC AGENTS

The influence of systemic arterial infusions of cholecystokinin octape ptide (CCK8) and somatostatin, and injections of cisapride, metoclopra mide and atropine on gastric emptying were studied in eight pigs. Gast ric emptying of dry matter (DM) and liquids (Cr-EDTA as marker) was me asured, in pigs fitted with a gastric cannula, by evacuation of gastri c contents either immediately after the pigs had finished feeding, or 3 h after being fed a meal containing 1200 g of a finely ground barley diet mixed with 2.41 water. Gastric emptying of DM and liquids during the feeding period was not significantly altered by cisapride (0.15 a nd 0.3 mg kg(-1-1)), metoclopramide (0.2 mg kg(-1)), CCK8 (250 ng kg(- 1) h(-1)) or somatostatin (1.8 and 4.5 mu g kg(-1) h(-1)); atropine (0 .06 mg kg(-1)) slowed emptying of DM (by 53 +/- 6 %; P < 0.001) and of liquids (by 51 +/- 7 %, P < 0.01), In contrast, the amount of DM empt ied within 3 h of feeding was significantly reduced with CCK8 (250 ng kg(-1) h(-1); by 14 +/- 3 %, P < 0.001) and with somatostatin (1.8 mu g kg(-1) h(-1); by 10 +/- 4%; P < 0.001). There was no increase in emp tying of DM or liquids with cisapride or metoclopramide; indeed, there was actually a reduction in liquid emptying (by 13 +/- 6%; P < 0.05) with cisapride (0.3 mg kg(-1)). Gastric emptying in the pig is then-fo re resistant both to stimulation by prokinetic agents, and to inhibiti on by some putative neurohormonal modulators at the doses used; gastri c emptying during feeding is even more resistant to alteration than is emptying between meals. It is concluded that in the pig, neither CCK nor somatostatin are involved in regulation of gastric emptying during the feeding period, but that both may play a minor role in regulation of emptying between meals. The low sensitivity to CCK may be a factor in the rapid gastric emptying of the pig.