Gastric wall tension determines perception of gastric distention

Background & Aims: The primary mechanism that originates symptoms in respon se to gastric distention remains undefined. The aim of this study was to de termine which factor, whether intragastric volume, pressure, or wall tensio n, determines perception of gastric distention. Methods: Healthy subjects u nderwent increasing gastric distentions (2-minute duration at 5-minute inte rvals) either at fixed pressure levels using a conventional barostat (n = 1 0) or at fixed tension levels using a newly developed computerized tensosta t (n = 12); perception was scored by a 0-6 scale. Distentions were performe d during basal conditions (intravenous saline) and during gastric relaxatio n by glucagon administration (4.8 mu g/kg intravenous bolus plus 9.6 mu g . kg(-1) . h(-1) infusion). Results: Isobaric distentions with the conventio nal barostat produced more intense perception during glucagon (95% +/- 40% higher; P < 0.05). However, the factor that determined higher perception co uld not be ascertained, because at the same pressure levels both intragastr ic volume and wall tension were greater during glucagon administration (174 % +/- 56% and 34% +/- 8% greater, respectively; P < 0.05 vs. saline for bot h). The tensostat evidenced that perception was selectively related to tens ion, not to elongation; during glucagon administration, intragastric volume s were significantly larger (80% +/- 28% larger increase; P < 0.05), but pe rception of isotonic distentions remained the same (27% +/- 22%; nonsignifi cant change). Conclusions: Gastric wall tension, but not intragastric volum e, determines perception of gastric distention, at least below nociception.