Our aim was to determine the role of intrinsic myoneural and enteric luminal continuity in the coordination of gastric and duodenal motility patterns. Three groups of dogs were prepared: five dogs with an intact gastrointestinal tract served as a Control group; four dogs had transection and reanastomosis of the duodenum 0.5 cm distal to the pylorus (Pyloric Transection group); and seven dogs had identical proximal duodenal transection, but with oversewing of duodenum and pylorojejunostomy to a Roux-en-Y limb (Roux-en-Y group). In the Control and Pyloric Transection groups, the gastric and intestinal MMCs were similar in appearance, the cycle durations (x ± SEM) were not different (134 ± 19 vs 111 ± 26 min, respectively; P > 0.05), and the times between the start of gastric and duodenal Phase III (gastroduodenal latency) were similar (6 ± 1 vs 10 ± 3 min; P > 0.05). In the Roux-en-Y group, MMCs also occurred in six of seven dogs but tended to have a longer cycle duration (176 ± 19 min) and a more variable gastroduodenal latency (23 ± 15 min). Plasma motilin concentration, measured only in the Roux-en-Y group, was greater during Phase III in the stomach and duodenum than during Phases I or II (P < 0.05). Feeding inhibited the gastric and duodenal MMCs in all groups, but the duodenal MMC returned earlier in the Roux-en-Y group. The Roux-en-Y jejunal limb exhibited a postprandial pattern in only seven of 14 studies. Luminal continuity and possibly plasma motilin concentration, but not necessarily intrinsic myoneural continuity, appear important in regulating temporal coordination of gastric and duodenal motor patterns during fasting and after feeding.
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