We have investigated the effect of bombesin on esophageal motility and explored the mechanism of action of bombesin. Eight healthy subjects were studied in random order during intravenous administration of (1) bombesin, (2) bombesin + vagal cholinergic receptor blockade with atropine and (3) bombesin + somatostatin. Lower esophageal sphincter pressure (LESP) and esophageal body motility were recorded continuously by Dent-sleeve manometry. Bombesin significantly (p < 0.01) increased LESP from 20 +/- 2 mmHg to 43 +/- 6 mmHg. Neither atropine nor somatostatin significantly reduced the bombesin-induced increases in LESP. Bombesin significantly (p<0.05) increased peristaltic wave amplitude (from 61 +/- 4 to 105 +/- 9 mmHg) and duration (from 2.9 +/- 0.2 to 4.8 +/- 0.3 s) in the mid and distal part of the esophagus. Neither atropine nor somatostatin significantly reduced the esophageal body motor response to bombesin. In conclusion (1) bombesin significantly increases LESP and affects esophageal body motility by increasing peristaltic wave amplitude and duration and (2) the effect of bombesin on esophageal motility is not dependent on vagal cholinergic mechanisms and is not mediated by the action of gastrointestinal hormones released by bombesin.