PHYSIOLOGICAL VARIATIONS IN CANINE GASTRIC TONE MEASURED BY AN ELECTRONIC BAROSTAT

Gastric tone may mediate gastric accommodation and emptying; however, it cannot be recorded by manometric methods. An electronic barostate was developed that maintains a constant pressure (2 mm Hg) within an airfilled bag and have validated the system in vitro and in vivo. In 4 conscious dogs, the bag was introduced orally into the stomach, and gastric tone was monitored from the barostat as variations in intrabag volume. Simultaneously, upper gut pressure activity was recorded by implanting manometric catheters. Studies were performed in fasting and fed (200-ml solid meal) dogs. The barostat system did not distort fasting motor activity. Intrabag volume correlated with manometrically measured fundic pressure activity. Tonic changes undetected manometrically were clearly registered by the barostat. Meals induced marked changes in gastric tone. A receptive relaxation during feeding was followed by a low-tone accommodation period. Later, the barostat registered a sustained high tone until the return of the fasting pattern. The electronic barostat measures physiological variations in gastric tone that are not recorded by conventional systems.