Mechanism of interdigestive migrating motor complex in conscious dogs. J Gastroenterol 2010 May;45(5):506-14
Date
12/25/2009Pubmed ID
20033824DOI
10.1007/s00535-009-0190-zScopus ID
2-s2.0-77953321807 (requires institutional sign-in at Scopus site) 38 CitationsAbstract
BACKGROUND: The migrating motor complex (MMC) is well characterized by the appearance of gastrointestinal contractions in the interdigestive state. This study was designed to clarify the mechanisms of gastric MMC (G-MMC) and intestinal MMC (I-MMC) in conscious dogs.
METHODS: Five strain gauge transducers were implanted on the stomach and intestine. To investigate the correlation between luminal 5-HT and phase III contractions, gastric and duodenal juices were collected during the MMC cycle. The 5-HT concentrations in gastric and duodenal juice were measured by HPLC. To investigate whether luminal 5-HT initiates MMC, 5-HT (10(-8)-10(-6) M, 10 ml) was administered into the duodenum 20 min after gastric phase III. To investigate the involvement of 5-HT(3) or 5-HT(4) receptors in mediating G-MMC and I-MMC, 5-HT(3) antagonists (ondansetron) or 5-HT(4) antagonists (GR 125,487) were infused for 120 min.
RESULTS: Luminal administration of 5-HT (10(-6) M) initiated duodenal phase II followed by G-MMC and I-MMC with a concomitant increased release of plasma motilin. The duodenal 5-HT concentration was significantly increased during phase II (59 +/- 9 ng/ml) and phase III (251 +/- 21 ng/ml) compared to that of phase I (29 +/- 5 ng/ml). On the other hand, the 5-HT content in the stomach was not significantly changed throughout the MMC cycle. Intravenous infusion of motilin (0.3 microg/kg/h) increased the luminal 5-HT content and induced G-MMC and I-MMC. 5-HT(4) antagonists significantly inhibited both G-MMC and I-MMC, while 5-HT(3) antagonists inhibited only G-MMC.
CONCLUSION: It is suggested that the MMC cycle is mediated by a positive feedback mechanism via the interaction between motilin and 5-HT.
Author List
Nakajima H, Mochiki E, Zietlow A, Ludwig K, Takahashi TAuthor
Kirk A. Ludwig MD Chief, Professor in the Surgery department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsConsciousness
Dogs
Duodenum
Female
Gastrointestinal Agents
Jejunum
Motilin
Mucous Membrane
Myoelectric Complex, Migrating
Pyloric Antrum
Serotonin
Serotonin Agents
Transducers, Pressure