[Use of an electronic barostat for measurement of motor response of the proximal stomach to feeding and different nervous stimuli in man].

Electronic barostat allows to measure volume variations of an intragastric air-filled bag maintained at a low constant pressure level, reflecting gastric tone variations. The aims of the present study were to record physiologic variations of gastric tone in humans a) in the fasting state, with and without different stimuli, and b) in the fed state. The bag was placed into the proximal stomach of healthy subjects and connected to the barostat. Volume variations were recorded in the basal state and in response to a) a balanced liquid meal (200 mL, 200 kcal, n = 8), b) sham feeding and sham feeding after cholinergic blockade (atropine 10 micrograms.kg-1 IV, n = 8), and c) graded antroduodenal distensions performed with a tandem balloon (n = 6). During fasting, the proximal stomach presented both a tonic and an intermittent phasic motor pattern (volume waves of 1.2 min maximal period). Meal ingestion was rapidly followed by a dramatic fall in proximal gastric tone (> 200% of preprandial volume within 11 +/- 5 min). After a meal, the intragastric bag returned to preprandial volume after 92 +/- 12 min (ranges: 75-110). Proximal gastric tone was not significantly modified by atropine or by sham feeding alone or after atropine. Antroduodenal distensions reproducibly induced volume dependent relaxations (r = 0.98, P < 0.001) with inhibition of the phasic activity. These results confirm the value of electronic barostat for the measurement of proximal gastric tone, and show that postprandial relaxation is not masked by a low volume liquid meal. Sham feeding does not appear to be an adequate stimulus to induce gastric relaxation. This suggests that vagal fibers involved in gastric relaxation are not the same (or have a higher stimulation threshold) than fibers involved in cephalic phase of gastric secretion.