Our aim was to determine the role of the extrinsic nerves in the regulation of the canine jejunoileal interdigestive myoelectric complex (IDMEC). In six dogs, the extrinsic nerves to the jejunoileum were completely divided by autotransplanting this segment of bowel. The proximal 75 cm of autotransplant were isolated as a modified Vella loop, while the remaining portion was left in situ. Electrodes were implanted on the duodenum and on the autotransplanted bowel for later recording of myoelectric activity. After 10 days, the conscious dogs were studied during fasting and after a meal of 200 g liver. During fasting, the IDMEC occurred not only in the innervated duodenum, but also in the autotransplanted segments of jejunoileum. However, the period of IDMEC was shorter in the autotransplanted segments (∼1.5 h) than in the duodenum (∼2.5 h), and a consistent temporal association of IDMEC between the three areas studied was not present. Moreover, feeding interrupted the IDMEC in the duodenum but not in the autotransplanted segments. We concluded that the extrinsic nerves to segments of jejunoileum were not necessary for the appearance of the IDMEC within such segments. However, extrinsic innervation and/or intrinsic myoneural or luminal continuity were necessary for temporal coordination of the IDMEC between segments of small intestine and for postprandial inhibition of the jejunoileal IDMEC.
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