THE EFFECT OF OCTREOTIDE ON HUMAN GASTRIC COMPLIANCE AND SENSORY PERCEPTION

Somatostatin or its analogue octreotide (OCT) has previously been show n to modulate gastric emptying, intestinal motor activity and visceral sensation. In the current study we sought to determine the effect of a single dose of OCT(1.25 mu g kg(-1) s.c.), which has previously been shown to have both motor and sensory effects, on proximal gastric com pliance and on conscious perception of gastric distention. Gastric dis tention was performed in 13 healthy male volunteers, by either slow ra mp distention (60 ml min(-1)) or by intermittent pressure steps (phasi c distention; 4-20 mmHg) using an electronic distention device. Compli ance curves (pressure-volume relationship), and thresholds for innocuo us (fullness) and noxious sensations (discomfort, pain) were determine d following vehicle or OCT injection. OCT consistently and significant ly reduced the rate of the gastric accommodation reflex by 50%, result ing in a reduced compliance at distention pressures greater than 10 mm Hg during phasic distention. In contrast, no effect was observed on th e compliance curve obtained during ramp distention. OCT selectively in creased the threshold for fullness during both ramp and phasic distent ion. During phasic distention, OCT decreased the volume thresholds for noxious (pain) sensations experienced at volumes greater than 300 ml, without affecting the corresponding pressure threshold. These finding s suggest that at low distension volumes, OCT in the dosage used has a direct inhibitory effect on afferents mediating innocuous gastric sen sations. The hyper algesic effect observed during phasic distention ma y be secondary to OCT's inhibitory effect on the gastric accommodation reflex.