Distal gastrectomy and Roux-Y limb in the rat : Plasma motilin, pancreatic polypeptide concentrations, and duodenojejunal motility

After gastrectomy, Roux-Y limb reconstruction leads to duodenojejunal motor disturbances. Because motilin and pancreatic polypeptide (PP) play a role in the regulation of digestive motility, their plasma concentrations were determined in rats after Roux-Y gastrectomy. Three months after a distal Roux-Y gastrectomy, coupling of electromyographic recordings and jugular samples were used to perform motilin and PP radioimmunoassays during and between activity fronts (AFs) occurring in the limb and in the duodenojejunum, 20, 40, and 60 min after intragastric instillation of a standard meal (5 ml Realmentyl). Animals that underwent a simple laparotomy, animals having isolated jejunal transection, and animals with Billroth I gastrectomy (BI group) served as control groups. After Roux-Y gastrectomy, the number of AFs in the limb (P < 0.01) and in the duodenum (P < 0.001) was reduced compared to laparotomized rats and the BI group, but did not differ from the number in the Tr group. In the limb, AFs were incompletely propagated or were retrograde in 9 and 3 of 20 animals, respectively. After Roux-Y gastrectomy, motilin concentrations occurred at the same time as each duodenal AF, and as in controls, and were independent from AFs in the limb. Plasma motilin concentrations were higher after Roux-Y reconstruction than in control groups (P < 0.03), and PP level concentrations were not different. After the meal, the interruption of AFs was shorter in Roux-Y reconstruction than in laparotomized and transected animals (P < 0.05) and than in BI group, with no significant difference in the latter. In all groups, plasma motilin and PP concentrations were decreased (P < 0.05) and increased (P < 0.001), respectively, after the meal compared to the interdigestive period. After Roux-Y gastrectomy, plasma motilin and PP levels were higher (P < 0.05) and lower (P < 0.05), respectively, compared to controls. In conclusion, AFs in the Roux-Y limb were not associated with plasma motilin concentrations, suggesting a lack of influence of motilin on the interdigestive motor status. The decrease in postprandial plasma PP concentrations may play a role in the shorter interruption of AFs after a meal.