Abstract
The effects of motilin infusions on periodic myoelectric spike activity were studied in conscious dogs with an intact small intestine and in dogs with established jejunal Thiry-Vella loops (T-V loops). Myoelectric activity was recorded from chronically implanted electrodes on the intact intestine, the anastomosed intestine and on the jejunal T-V loop. During fasting, migrating myoelectric complexes (m.m.c.) were present in the intact and anastomosed intestine and in the T-V loop; in the latter, intervals between m.m.c. were significantly shorter (P < 0.05). Infusion of motilin induced premature m.m.c. in the intact and anastomosed intestine, reducing the interval between successive m.m.c. (P < 0.05). In contrast, in the T-V loop, motilin significantly reduced the number of m.m.c. (P < 0.01) and the interval between 2 m.m.c. was prolonged. After an infusion of motilin, the number of m.m.c. in the intact and anastomosed intestine was significantly reduced (P < 0.01), with a corresponding increase in the intervals between m.m.c.; no further changes were observed in the T-V loop. M.m.c. are induced by motilin in the proximal gut, suggesting a humoral mechanism for m.m.c. initiation in this region. The genesis of m.m.c. in jejunal T-V loops is delayed by motilin.