Chronic stress-induced alterations in mouse colonic 5-HT and defecation responses are strain dependent

Marcela Julio-Pieper, Cliona M. O'Mahony, Gerard Clarke, Javier A. Bravo, Timothy G. Dinan, John F. Cryan

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Mood disorders and chronic stress are frequently associated with gastrointestinal (GI) symptoms including diarrhoea or constipation. Locally produced serotonin [5-hydroxytryptamine (5-HT)] regulates GI motility and is a key factor in the pathophysiology of stress-associated GI disorders. We aimed to establish whether chronic stress can differentially affect faecal output and colon 5-HT concentration in two inbred mouse strains: BALB/c and C57BL/6 which differ in their ability to cope with stress. Adult male BALB/c and C57BL/6 mice were restrained for 2 h daily for 10 days. Defecation was monitored during each stress session. Twenty-four hours after the last session of stress, plasma corticosterone concentration was higher than control in both strains, indicative of a physiological effect of chronic stress; however, stress-induced diarrhoea was more persistent in C57BL/6 mice. Basal concentration of colon 5-HT was higher in C57BL/6 mice, and stress elicited an increase in colon 5-HT only in this strain. Finally, nave BALB/c mice had a higher sensitivity (incidence of diarrhoea) to 5-HT (0.33 mg/kg, i.p.) than C57BL/6 mice. Our results suggest that differential defecation responses to stress may be associated with colon 5-HT concentration, which may in turn reflect the individual sensitivity to 5-HT. In addition, C57BL/6 mice emerge as a relevant model for studying GI alterations induced by chronic stress.

Original languageEnglish
Pages (from-to)218-226
Number of pages9
Issue number2
StatePublished - Mar 2012
Externally publishedYes


  • Anxiety
  • Braingut axis
  • Depression
  • Diarrhoea
  • Irritable bowel syndrome
  • Serotonin


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