Giant migrating contractions of the canine cecum.

We investigated cecal motor activity and its coordination with ileal and colonic motor activities in five conscious dogs instrumented with strain-gauge transducers. Both ileum and colon exhibited the usual migrating motor complexes (MMCs) that were independent of each other. Cecum had no motor complexes, but it periodically generated giant migrating contractions (GMCs) that originated at the apex and migrated to the cecum-colonic junction at a velocity of 13 +/- 1.3 cm/min. The amplitude of cecal GMCs was 1.82 +/- 0.26 and 3.37 +/- 0.39 times larger than that of contractions during ileal and colonic motor complexes, respectively (P less than 0.05). The mean duration and period of cecal GMCs were 45 +/- 4 s and 61.4 +/- 14.2 min, respectively, in the fasted state and 49 +/- 6 s and 68.5 +/- 13.5 min in the fed state, respectively (P less than 0.05). A total of 82 cecal GMCs was recorded in 71 h of fasted recording and 94 in 121 h of fed recording. Cecal GMCs were not coordinated with colonic MMCs. Intravenous motilin, but not morphine, initiated a premature cecal GMC. We concluded that cecum has a unique motor activity that is different from that of the colon and the ileum. The strong caudad GMCs of the cecum may periodically empty cecal contents into the colon.