Faculty Collaboration Database

Endogenous ghrelin and 5-HT regulate interdigestive gastrointestinal contractions in conscious rats. Am J Physiol Gastrointest Liver Physiol 2008 Aug;295(2):G403-11

Date

06/21/2008

Pubmed ID

18566321

DOI

10.1152/ajpgi.90260.2008

Scopus ID

2-s2.0-52449114280 (requires institutional sign-in at Scopus site)   31 Citations

Abstract

Endogenous ghrelin causes interdigestive contractions of the stomach in rats. In contrast, previous studies showed that 5-HT(3) and 5-HT(4) receptors were involved in regulating intestinal interdigestive contractions. We studied the possible role of endogenous ghrelin and 5-HT regulating interdigestive gastrointestinal (GI) contractions in rats. Four strain gauge transducers were implanted on the antrum, duodenum, and proximal and distal jejunum. After an overnight fast, GI contractions were recorded in freely moving conscious rats and ghrelin receptor antagonists [(d-lys3)GHRP6; 1 micromol/kg], 5-HT(3) antagonists (Ondansetron; 0.5 mg/kg) and 5-HT(4) antagonists (GR 125,487; 1 mg/kg) were administered (bolus iv). To evaluate the relationship between the luminal concentrations of 5-HT and phase III-like contractions of the duodenum, duodenal juice was collected via the intraduodenal catheter. 5-HT content of the duodenal juice was measured by HPLC. (d-lys3)GHRP6 significantly attenuated the occurrence and amplitude of phase III-like contractions of the antrum, but not the duodenum and jejunum. 5-HT(4) antagonists significantly reduced spontaneous phase III-like contractions of the jejunum, without affecting those of the antrum and duodenum. In contrast, 5-HT(3) antagonists did not affect phase III-like contractions in GI tract. Luminal concentration of 5-HT at the phase III-like contraction (36.0 +/- 13.3 ng/ml, n = 9) was significantly higher than that at the phase I-like contractions of the duodenum (4.9 +/- 1.6 ng/ml, n = 9, P < 0.05). It is suggested that released ghrelin from the gastric mucosa mediates gastric phase III-like contractions, whereas 5-HT released from enterochromaffin cells of the duodenal mucosa mediates intestinal phase III-like contractions via 5-HT(4) receptors.

Author List

Taniguchi H, Ariga H, Zheng J, Ludwig K, Mantyh C, Pappas TN, Takahashi T

Author

Kirk A. Ludwig MD Chief, Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Duodenum
Gastrointestinal Motility
Ghrelin
Growth Hormone-Releasing Hormone
Indoles
Male
Muscle Contraction
Oligopeptides
Ondansetron
Postprandial Period
Rats
Rats, Sprague-Dawley
Serotonin
Sulfonamides
Vagotomy