The aim was to investigate the integration of proximal gastric, antral, pyloric, and duodenal motility during fasting and after feeding. Using a proximal gastric barostat and a manometric assembly with an array of side holes astride the gastroduodenal junction, the gastrointestinal interdigestive migrating motor complex was detected in five of seven conscious fasting dogs. During phase III of the complex, which lasted a mean +/- SEM of 13 +/- 0.5 min, 9.6 +/- 0.9 volume waves were present in the proximal stomach. The volume waves were coordinated with clusters of antral waves 64 +/- 11% of the time and with inhibition of duodenal waves 91 +/- 3% of the time. A 300-ml calorie-dense liquid meal abolished the complex and promptly increased proximal gastric volume in five of six dogs. Volume waves were nearly completely suppressed, while antral waves decreased from 24 +/- 3.0 waves/10 min to 10 +/- 2.8 waves/10 min (P < 0.05) and isolated pyloric pressure waves increased from 7.2 +/- 2.8 waves/10 min to 22 +/- 3.3 waves/10 min (P < 0.005). In summary, proximal gastric motility was integrated with antral, pyloric, and duodenal motility under both fasting and fed conditions. The integrated patterns likely account for the efficient clearance of indigestible solids during fasting and the controlled emptying of nutrients with feeding.