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Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Nov 7, 2008; 14(41): 6299-6302
Published online Nov 7, 2008. doi: 10.3748/wjg.14.6299
Effects of ghrelin on interdigestive contractions of the rat gastrointestinal tract
Hiroshi Taniguchi, Hajime Ariga, Jun Zheng, Kirk Ludwig, Toku Takahashi
Hiroshi Taniguchi, Hajime Ariga, Jun Zheng, Kirk Ludwig, Toku Takahashi, Department of Surgery, Medical College of Wisconsin and Zablocki VA Medical Center, Milwaukee, Wisconsin, United States
Author contributions: Taniguchi H, Ariga H and Zheng J performed research; Taniguchi H, Ludwig K and Takahashi T analyzed the data; Taniguchi H and Takahashi T wrote the paper.
Correspondence to: Toku Takahashi, MD, PhD, Department of Surgery, Medical College of Wisconsin and Zablocki VA Medical Center, 5000 West National Avenue, Milwaukee, WI 53295, United States. ttakahashi@mcw.edu
Telephone: +1-414-3842000-41472 Fax: +1-414-3825374
Received: October 15, 2008
Revised: October 30, 2008
Accepted: November 6, 2008
Published online: November 7, 2008
Abstract

Ghrelin causes interdigestive contractions of the stomach in rats. However, it remains unknown whether ghrelin causes interdigestive contractions in the small intestine. Four strain gauge transducers were implanted on the antrum, duodenum, proximal and distal jejunum. After an overnight fast, gastrointestinal (GI) contractions were recorded in freely moving conscious rats. Spontaneous phase III-like contractions were observed at every 13-16 min in rat GI tract. The fasted motor patterns were replaced by the fed motor pattern immediately after food intake. Two minutes after finishing the spontaneous phase III-like contractions in the antrum, acyl ghrelin (0.8, 2.4 and 8.0 μg/kg per min) was continuously infused for 30 min. Three-five minutes after the starting ghrelin infusion, augmented phase III-like contractions were observed at the antrum, duodenum, and jejunum. Ghrelin infusion (0.8, 2.4 and 8.0 μg/kg per min) significantly increased motility index of phase III-like contractions at the antrum and jejunum in a dose dependent manner, compared to that of saline injection. Thus, it is likely that exogenously administered ghrelin causes phase III-like contraction at the antrum, which migrates to the duodenum and jejunum. The possible role of 5-HT, in addition to ghrelin, in mediating intestinal migrating motor complex (MMC), is discussed.

Keywords: Phase III-like contractions; Strain gage transducers; Motility index