Affiliation:
1. Gastrointestinal Diseases Research Unit Queen's University Kingston Ontario Canada
2. Department of Dietetics, Nutrition and Sport La Trobe University Melbourne Victoria Australia
Abstract
AbstractBackgroundMonosodium glutamate (MSG) has been identified as a trigger of abdominal pain in irritable bowel syndrome (IBS), but the mechanism is unknown. This study examined whether MSG causes visceral hypersensitivity using a water‐avoidance stress (WAS) mouse model of visceral pain.MethodsMice were divided into four groups receiving treatment for 6 days: WAS + MSG gavage, WAS + saline gavage, sham‐WAS + MSG gavage, and sham‐WAS + saline gavage. The acute effects of intraluminal administration of 10 μM MSG on jejunal extrinsic afferent nerve sensitivity to distension (0–60 mmHg) were examined using ex vivo extracellular recordings. MSG was also applied directly to jejunal afferents from untreated mice. Glutamate concentration was measured in serum, and in the serosal compartment of Ussing chambers following apical administration.Key ResultsAcute intraluminal MSG application increased distension responses of jejunal afferent nerves from mice exposed to WAS + MSG. This effect was mediated by wide dynamic range and high‐threshold units at both physiologic and noxious pressures (10–60 mmHg, p < 0.05). No effect of MSG was observed in the other groups, or when applied directly to the jejunal afferent nerves. Serum glutamate was increased in mice exposed to WAS + MSG compared to sham‐WAS + saline, and serosal glutamate increased using WAS tissue (p = 0.0433).Conclusions and InferencesThese findings demonstrate that repeated exposure to MSG in mice leads to sensitization of jejunal afferent nerves to acute ex vivo exposure to MSG. This may contribute to visceral hypersensitivity reported in response to MSG in patients with IBS.
Funder
Canadian Institutes of Health Research
Canadian Nutrition Society
Nestlé Health Science
Queen's University
Subject
Gastroenterology,Endocrine and Autonomic Systems,Physiology
Cited by
2 articles.
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