Plasma Hormones Facilitated the Hypermotility of the Colon in a Chronic Stress Rat Model

Chengbai Liang,Ying Liu,Hesheng Luo,Jiwang Cao,Hong Xia,Alice Y W Chang

doi:10.1371/journal.pone.0031774

Chengbai Liang, Ying Liu + Show 4 more

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https://doi.org/10.1371/journal.pone.0031774

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Journal: PloS one	Publication Date: Feb 20, 2012
Citations: 26	License type: CC BY 4.0

Affiliation: Wuhan University, Renmin Hospital of Wuhan University

Abstract

ObjectiveTo study the relationship between brain-gut peptides, gastrointestinal hormones and altered motility in a rat model of repetitive water avoidance stress (WAS), which mimics the irritable bowel syndrome (IBS).MethodsMale Wistar rats were submitted daily to 1-h of water avoidance stress (WAS) or sham WAS (SWAS) for 10 consecutive days. Plasma hormones were determined using Enzyme Immunoassay Kits. Proximal colonic smooth muscle (PCSM) contractions were studied in an organ bath system. PCSM cells were isolated by enzymatic digestion and IKv and IBKca were recorded by the patch-clamp technique.ResultsThe number of fecal pellets during 1 h of acute restraint stress and the plasma hormones levels of substance P (SP), thyrotropin-releasing hormone (TRH), motilin (MTL), and cholecystokinin (CCK) in WAS rats were significantly increased compared with SWAS rats, whereas vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and corticotropin releasing hormone (CRH) in WAS rats were not significantly changed and peptide YY (PYY) in WAS rats was significantly decreased. Likewise, the amplitudes of spontaneous contractions of PCSM in WAS rats were significantly increased comparing with SWAS rats. The plasma of WAS rats (100 µl) decreased the amplitude of spontaneous contractions of controls. The IKv and IBKCa of PCSMs were significantly decreased in WAS rats compared with SWAS rats and the plasma of WAS rats (100 µl) increased the amplitude of IKv and IBKCa in normal rats.ConclusionThese results suggest that WAS leads to changes of plasma hormones levels and to disordered myogenic colonic motility in the short term, but that the colon rapidly establishes a new equilibrium to maintain the normal baseline functioning.

Highlights

The irritable bowel syndrome (IBS) is defined as a chronic and recurrent functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and altered bowel habits in the absence of any detectable structural abnormalities or infection on routine testing [1,2]
The fecal pellet output in all animals was significantly increased by water avoidance stress (WAS) with exposure to the water for 1 hour, and was more for the first five days (FFD) than for the last five days (LFD) (6.1460.69 vs. 4.8860.50, p,0.01, Figure 1)
There was no such effect with exposure to sham stress (2.4660.67 vs. 2.4260.23, p.0.05, Figure 1)

Summary

Introduction

The irritable bowel syndrome (IBS) is defined as a chronic and recurrent functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and altered bowel habits in the absence of any detectable structural abnormalities or infection on routine testing [1,2]. Many studies have shown that IBS patients have various gastrointestinal (GI) motor disturbances that often arise from an exaggerated physiological response to stimuli such as diet and stress [7,8]. The stress changes their bowel patterns and produces abdominal pain [9]. IBS patients tend to be more vulnerable to stressful events in daily life [13] They may have an increased incidence of other functional, somatoform disorders, as demonstrated by an increased incidence of ‘‘prostatitis syndrome’’ (PS) or IBS in patients who have one or the other disorder [14]

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