The aim of this study was to evaluate possiblechanges in the neuropeptide innervation pattern of theremaining porcine ileum following 75% proximal resectionof the small intestine. Three-month-old piglets were operated on and two months postoperativelyfullthickness specimens of the proximal part of thedistal ileum wall were taken. Age-matched 3- and5-month-old unoperated piglets were used as controls. The number and intensity of VIP-, galanin-,enkephalin-, substance P-, and somatostatin-containingnerve fibers were estimated in sections processed forimmunofluorescence microscopy and subjected toquantitative scoring. The VIP-, galanin-, andenkephalin-immunoreactive fibers of the circular musclelayer and villi were also quantitated bycomputer-assisted morphometry. The number and intensityof VIP-immunoreactive fibers in the mucosa and circular muscle layermarkedly decreased after resection as compared to3-month-old and 5-month-old controls (P < 0.05). Thegalanin immunoreactivity index decreased significantly after resection in the circular muscle layer ascompared to both control groups (P < 0.05). Theincrease in the number of enkephalin-immunoreactivenerve fibers that normally occurred from 3 to 5 monthsof age was inhibited by the resection. We were notable to see any differences in somatostatin or substanceP immunoreactivity between the groups. The resultssuggest that massive resection induces significant changes in the neuropeptide-containinginnervation of the remaining small intestine. Thesefindings are compatible with altered motor activity andmucosa function in the remain intestine.