LAUSR

ABSTRACT Stress‐induced altered visceral sensation and impaired gut barrier play an important role in the pathophysiology of irritable bowel syndrome (IBS). These responses were demonstrated to be peripheral corticotropin‐releasing factor (CRF) dependent and also mediated via proinflammatory cytokine in animal IBS model. Dehydroepiandrosterone sulfate (DHEA‐S) is known to have anti‐inflammatory properties by suppressing proinflammatory cytokine release. We hypothesized that DHEA‐S improves stress‐induced visceral changes and is beneficial for IBS treatment. We explored the effects of DHEA‐S on lipopolysaccharide (LPS)‐ or repeated water avoidance stress (WAS)‐induced visceral allodynia and increased colonic permeability (rat IBS models). The threshold of visceromotor response, i.e. abdominal muscle contractions induced by colonic balloon distention was electrophysiologically measured. Colonic permeability was estimated in vivo by quantifying the absorbed Evans blue in colonic tissue. DHEA‐S abolished visceral allodynia and colonic hyperpermeability induced by LPS in a dose‐dependent manner. It also blocked repeated WAS‐ or peripheral injection of CRF‐induced visceral changes. These effects by DHEA‐S in LPS model were reversed by bicuculline, a &ggr;‐aminobutyric acid (GABA)A receptor antagonist, NG‐nitro‐L‐arginine methyl ester, a nitric oxide (NO) synthesis inhibitor, naloxone, an opioid receptor antagonist, or sulpiride, a dopamine D2 receptor antagonist. However, domperidone, a peripheral dopamine D2 receptor antagonist did not modify the effects. Peripheral injection of astressin2‐B, a selective CRF receptor subtype 2 (CRF2) antagonist also reversed these effects. In conclusion, DHEA‐S blocked stress‐induced visceral changes via GABAA, NO, opioid, central dopamine D2 and peripheral CRF2 signaling. DHEA‐S may be useful for IBS treating.