The influence of systemic arterial infusions of cholecystokinin octapeptide (CCK8) and somatostatin, and injections of cisapride, metoclopramide and atropine on gastric emptying were studied in eight pigs. Gastric emptying of dry matter (DM) and liquids (Cr-EDTA as marker) was measured, in pigs fitted with a gastric cannula, by evacuation of gastric 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 and 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 micrograms 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 emptied 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 microgram kg-1 h-1; by 10 +/- 4%; P < 0.001). There was no increase in emptying 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).(ABSTRACT TRUNCATED AT 250 WORDS)