Differences in the sensorimotor response to distension between the proximal and distal stomach in humans

Background: It is not known which region of the stomach is responsible for symptom generation or whether symptoms induced by gastric distension are region specific. Also, it is unclear whether low level gastric distension has a modulatory role on gastric tone and mechanosensitivity. Aims: To define differences in the sensorimotor response to distension between proximal and distal gastric distension, and to determine the effects of low level gastric distension on gastric tone and mechanosensitivity. Methods: In 14 healthy volunteers, a double barostat assembly incorporating a distal ( antral) and proximal ( fundic) bag was introduced into the stomach. Pressure sensitivity tests with either bag were performed with and without simultaneous background distension of the other bag in a randomised manner. Proximal gastric accommodation to a meal was measured with and without simultaneous distal gastric distension. Results: The distal stomach was less compliant than the proximal stomach to low level distension. Thresholds for first perception and discomfort, and symptom profiles did not differ between distal and proximal gastric distension. Simultaneously applied low level gastric distension of one segment did not affect gastric mechanosensitivity of the other segment. Both the proximal and distal stomach relax after ingestion of a meal. Simultaneous low level antral distension decreases proximal gastric accommodation to a meal. Conclusions: Compared with the proximal stomach, the distal stomach is less compliant but its mechanosensitivity is not different. Symptoms induced by gastric distension are not region specific and no spatial summation occurred. Meal induced relaxation occurs both in the proximal and distal stomach.