Somatostatin induces ectopic activity fronts via a local intestinal mechanism during fed state or pentagastrin

The effect of local intra-arterial infusions of somatostatin on small bowel motility in the postprandial period and during an intravenous pentagastrin infusion was studied in five dogs. A Silastic catheter was implanted in a small branch of the superior mesenteric artery perfusing a 5-to 10-cm jejunal segment located 30-40 cm distally to Treitz. Small bowel myoelectric activity was recorded by means of a series of bipolar electrodes implanted subserosally along the small intestine. Experiments were started 2 wk after surgery and were performed in conscious animals. Intra-arterial infusion of somatostatin induced activity fronts in the fed state and during intravenous pentagastrin infusion in a dose-dependent manner. These activity fronts always started at or just below the perfused segment, migrated distally over the remaining small bowel, and were superimposed on the fed pattern. We conclude that local administration of somatostatin is able to initiate normally migrating ectopic activity fronts, despite the presence of neural and hormonal factors that control the fed state. Local release of somatostatin might be involved in the initiation of spontaneously occurring activity fronts.