Effect of Massive Small Bowel Resection on Components of the Peptidergic Innervation of the Rat Small Intestine

Abstract

The effect of massive small bowel resection on the immunostaining of neuropeptides in the submucous plexus of the retained small intestine was examined. The neuropeptides chosen were somatostatin and vasoactive intestinal polypeptide because these are markers for two of the major populations of neurons in the plexus. Three different methods were used to assess the effect of resection on the enteric nervous system. Firstly immunocytochemical staining of neuropeptide containing neurons and nerve fibers was compared between test and control animals. The results demonstrated a significant increase in the number and size of the vasoactive intestinal polypeptide containing neurons with no change in the number of somatostatin neurons although these were also increased in size. Secondly the possibility that the increase in neuron number might be the result of neuronal division was examined by ³H-thymidine incorporation experiments. The results demonstrated that no neuronal elements were labelled. Finally the possibility that the increase in vasoactive intestinal peptide was the result of an increase in transcription was assessed by Northern blot analysis. The results demonstrated a small but significant increase in mRNA levels. It was concluded that massive small bowel resection directly affects neuropeptide levels in the submucous plexus, resulting in an increase in vasoactive intestinal polypeptide-immunoreactive neurons.

Vagal afferents are essential for maximal resection-induced intestinal adaptive growth in orally fed rats

“…This supports previous findings that luminal nutrients are a major stimulus for mucosal cell proliferation and intestinal adaptation (10,32). Luminal nutrients increase pancreaticobiliary secretions, gut neuronal/vagal activity, splanchnic blood flow, and secretion of hormones that may stimulate gut growth directly or indirectly (6,14,21).…”

“…The interactions between luminal nutrients and neuroendocrine signals in the stimulation of intestinal adaptive growth are poorly understood; however, GLP-2 is thought to be a key hormonal mediator (6,10,13,21,36,42). We have investigated how partial functional ablation of vagal afferent input Values are means Ϯ SE; n ϭ 9 -13 rats group.…”

Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats

“…Further, the correlation of nNOS with crypt cell kinetics and muscle thickness was consistent with other reports demonstrating a regulatory role for nitric oxide and the myenteric plexus in jejunal crypt cell proliferation [41, 42]. Although we did not detect any changes in the ratio of VIP staining neurons, previous studies have described inhibitory and stimulatory effects of proximal and mid bowel resection on VIP abundance in the ENS [43, 44]. Inconsistencies in results could be due to the absence of transected bowel controls, or the effect of location and extent of resection on specific neuroeffectors [43–46].…”

Somatostatin as an Active Substance in the Mammalian Enteric Nervous System

“…Interestingly, the previous studies reported more than once that strong pathological stimuli, which are known to influence the neurochemical characterization of the enteric neurons, have no effect on the number of SOM-immunoreactive nervous structures in the GI tract. Such a situation has been noted, among others, in the human colon during Hirschsprung disease [54], within the human pylorus during hypertrophic pyloric stenosis [21], and after massive bowel resection in the rat small intestine, although in the latter case a clear increase in the size of SOM-positive enteric neurons was reported [95]. A summary of the existing observations concerning the changes in the number of SOM-positive nervous structures in the wall of the GI tract under various stimuli is presented in Table 2.…”