Volume 32, Issue 6 e13819
ORIGINAL ARTICLE

Losartan improves visceral sensation and gut barrier in a rat model of irritable bowel syndrome

Tsukasa Nozu

Corresponding Author

Tsukasa Nozu

Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Japan

Center for Medical Education, Asahikawa Medical University, Asahikawa, Japan

Correspondence

Tsukasa Nozu, Department of Regional Medicine and Education, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido, 078-8510, Japan.

Email: [email protected]

Search for more papers by this author
Saori Miyagishi

Saori Miyagishi

Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Japan

Search for more papers by this author
Rintaro Nozu

Rintaro Nozu

Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Japan

Search for more papers by this author
Kaoru Takakusaki

Kaoru Takakusaki

Research Center for Brain Function and Medical Engineering, Asahikawa Medical University, Asahikawa, Japan

Search for more papers by this author
Toshikatsu Okumura

Toshikatsu Okumura

Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Japan

Department of General Medicine, Asahikawa Medical University, Asahikawa, Japan

Search for more papers by this author
First published: 14 February 2020
Citations: 11

Abstract

Background

Lipopolysaccharide (LPS) or repeated water avoidance stress (WAS) induces visceral allodynia and colonic hyperpermeability via corticotropin-releasing factor (CRF) and proinflammatory cytokines, which is considered to be a rat irritable bowel syndrome (IBS) model. As losartan is known to inhibit proinflammatory cytokine release, we hypothesized that it improves these visceral changes.

Methods

The threshold of visceromotor response (VMR), that is, abdominal muscle contractions induced by colonic balloon distention was electrophysiologically measured in rats. Colonic permeability was determined in vivo by quantifying the absorbed Evans blue in colonic tissue for 15 minutes spectrophotometrically.

Key Results

Lipopolysaccharide (1 mg kg−1) subcutaneously (s.c.) reduced the threshold of VMR and increased colonic permeability. Losartan (5-25 mg kg−1 s.c.) for 3 days inhibited these changes in a dose-dependent manner. Moreover, repeated WAS (1 hour daily for 3 days) or intraperitoneal injection of CRF (50 µg kg−1) induced the similar visceral changes as LPS, which were also eliminated by losartan. These effects by losartan in LPS model were reversed by GW9662 (a peroxisome proliferator-activated receptor-γ [PPAR-γ] antagonist), NG-nitro-L-arginine methyl ester (a nitric oxide [NO] synthesis inhibitor), or naloxone (an opioid receptor antagonist). Moreover, it also inhibited by sulpiride (a dopamine D2 receptor antagonist) or domperidone (a peripheral dopamine D2 antagonist).

Conclusion & Inferences

Losartan prevented visceral allodynia and colonic hyperpermeability in rat IBS models. These actions may be PPAR-γ–dependent and also mediated by the NO, opioid, and dopamine D2 pathways. Losartan may be useful for IBS treatment.

CONFLICTS OF INTEREST

The authors declare no conflicts of interests.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.