Repeated psychological stress-induced alterations of visceral sensitivity and colonic motor functions in mice: Influence of surgery and postoperative single housing on visceromotor responses

Abstract

Visceral pain modulation by chronic stress in mice has been little studied. Electromyography (EMG) recording of abdominal muscle contractions, as a proxy to the visceromotor response (VMR), requires electrode implantation and post-surgical single housing (SH) which could affect the VMR to stress. To test this hypothesis, male mice had electrode implantation surgery (S) plus SH, or no surgery and were group housed (NS-GH) or single housed (NS-SH) and exposed to either water avoidance stress (WAS, 1 h/day) or left undisturbed in their home cages for 10 days. The VMR to phasic ascending colorectal distension (CRD) was assessed before (basal) and 24 h after 10 days of WAS or no stress using a surgery-free method of intraluminal colonic pressure (ICP) recording (solid-state manometry). WAS heightened significantly the VMR to CRD at 30, 45, and 60 mmHg in S-SH vs. NS-GH, but not compared to NS-SH conscious mice. Compared to basal CRD, WAS increased VMR at 60 mmHg in the S-SH group and decreased it at 30–60 mmHg in NS-GH mice, while having no effect in NS-SH mice. The average defecation during the hour of repeated WAS over 10 days was 1.9 and 2.4 fold greater in S-SH vs. NS-GH and NS-SH mice, respectively. These data indicate that the combination of S-SH required for VMR monitoring with EMG is an important component of repeated WAS-induced post-stress visceral hypersensitivity and defecation in mice.

The Irritable Bowel Syndrome: How Stress Can Affect the Amygdala Activity and the Brain-Gut Axis

“…However, habituation of the CRFergic system is observed in chronic conditions (Bonaz and Rivest 1998) and may induce analgesia. It seems that these conflicting data are influenced by the basal state conditions of the animals before applying the repeated stressor (surgery and single housing) (Larauche, et al 2010). …”

Genotype-dependent responsivity to inflammatory pain: A role for TRPV1 in the periaqueductal grey

“…Adult male C57Bl/6 mice 1hr per day for 10 consecutive days Colorectal distension Visceral hyperalgesia (Hong et al, 2009a;Larauche et al, 2010) Mechanical and Visceral hyperalgesia (Green et al, 2011b;Khasar et al, 2009Khasar et al, , 2005 Chronic Mild Stress…”

Modulation of Visceral Pain by Stress: Implications in Irritable Bowel Syndrome

“…Even though no data are available in the literature in relation to the immune impact of chronic EMG electrodes placed into the abdominal wall, such intervention could induce a host-tissue response with local micro-inflammation (neutrophils, lymphocytes and macrophages) as it has been shown for other types of implants in the skin and peritoneum (Klueh & Kreutzer, 2005). A recent report suggests that the preconditions of animals (EMG surgery, post-surgical delivery of antibiotic and single housing) have a considerable impact on the visceral pain responses to CRD, particularly in the context of stress studies (Larauche et al, 2010). Other approaches consist of recording manometric changes in the pressure of the balloon inserted into the distal colon (Arvidsson et al, 2006) or changes in pressure inside the colonic lumen Larauche et al, 2010).…”

“…A recent report suggests that the preconditions of animals (EMG surgery, post-surgical delivery of antibiotic and single housing) have a considerable impact on the visceral pain responses to CRD, particularly in the context of stress studies (Larauche et al, 2010). Other approaches consist of recording manometric changes in the pressure of the balloon inserted into the distal colon (Arvidsson et al, 2006) or changes in pressure inside the colonic lumen Larauche et al, 2010). These two techniques present the advantage of being minimally invasive as they do not require surgery and post-surgical treatments such as antibiotics or analgesics which can affect the visceral pain responses and still remain an objective and sensitive measure of abdominal contractions.…”

“…However, as more stringent brain imaging approaches are developed in rodents, they will open new venues to parallel human studies (Coello et al, 2011;Lee et al, 2010). We recently developed an alternative non-invasive method to study visceral sensitivity to CRD in conscious mice, using a commercially-available miniaturized pressure catheter to record intraluminal colonic pressure (ICP) (Larauche et al, 2010). Briefly, a PE50 catheter was taped 2 cm below the pressure sensor of a miniaturized pressure transducer catheter (SPR-524 Mikro-Tip catheter; Millar Instruments, Houston, TX).…”