Background: The current view holds that gastric emptying is effected by the force of the antral peristaltic wave squeezing food particles through pyloric sphincter resistance. Whether this is accomplished by a refl ex action was investigated.
Material/Methods: The study comprised 12 healthy volunteers (age: 42.2±10.6 years). A balloon-tipped and a manometric tube were introduced into the stomach. Pressure responses in the proximal stomach, pyloric antrum, and pyloric sphincter to distension of the proximal stomach and of the antrum were
recorded. Pyloric sphincter distension was induced to test its effect on antral and proximal stomach pressure. These tests were repeated in nine men after separately anesthetizing the pyloric antrum and sphincter.
Results: Distension of the proximal stomach produced no pressure changes in the proximal stomach, pyloric antrum, or sphincter (p>0.05). Antral distension effected a signifi cant rise in antral pressure, but not in the proximal stomach. Signifi cant sphincter pressure decrease occurred only with antral
distension volumes >50 ml. Pyloric sphincter distension produced a signifi cant rise in antral pressure, but not in the proximal stomach. Sphincteric or antral anesthetization produced no pressure changes in the pyloric sphincter, antrum, or proximal stomach.
Conclusions: Pyloric sphincter relaxation upon antral distension implies a refl ex relationship the authors call the “antro-sphincteric inhibitory refl ex”. Pyloric sphincter distension effected antral contraction, which is suggested to be a refl ex in nature and which they term the “sphinctero-antral excitatory refl ex”. It is postulated that these two refl exes act to churn and transport gastric contents to the duodenum.

Keywords: Anesthesia, Local, Carbon Dioxide, Gastric Emptying - physiology, Pressure, Pyloric Antrum - physiology, Pylorus - physiology