Bassil AK, Häglund Y, Brown J, Rudholm T, Hellström PM, Näslund E, Lee K, Sanger GJ. Little or no ability of obestatin to interact with ghrelin or modify motility in the rat gastrointestinal tract.
Br J Pharmacol 2007;
150:58-64. [PMID:
17128285 PMCID:
PMC2013842 DOI:
10.1038/sj.bjp.0706969]
[Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 10/11/2006] [Accepted: 10/16/2006] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE
Obestatin, encoded by the ghrelin gene may inhibit gastrointestinal (GI) motility. This activity was re-investigated.
EXPERIMENTAL APPROACH
Rat GI motility was studied in vitro (jejunum contractility and cholinergically-mediated contractions of forestomach evoked by electrical field stimulation; EFS) and in vivo (gastric emptying and intestinal myoelectrical activity). Ghrelin receptor function was studied using a GTPgammaS assay and transfected cells.
KEY RESULTS
Contractions of the jejunum or forestomach were unaffected by obestatin 100 nM or 0.01-1000 nM, respectively (P>0.05 each; n=4-18). Obestatin (0.1-1 nM) reduced the ability of ghrelin 1 microM to facilitate EFS-evoked contractions of the stomach (increases were 42.7+/-7.8% and 21.2+/-5.0 % in the absence and presence of obestatin 1 nM; P<0.05; n=12); higher concentrations (10-1000 nM) tended to reduce the response to ghrelin but changes were not statistically significant. Similar concentrations of obestatin did not significantly reduce a facilitation of contractions caused by the 5-HT(4) receptor agonist prucalopride, although an inhibitory trend occurred at the higher concentrations (increases were 69.3+/-14.0% and 42.6+/-8.7% in the absence and presence of 1000 nM obestatin; n=10). Obestatin (up to 10 microM) did not modulate recombinant ghrelin receptor function. Ghrelin increased gastric emptying and reduced MMC cycle time; obestatin (1000 and 30,000 pmol kg(-1) min(-1)) had no effects. Obestatin (2500 pmol kg(-1) min(-1), starting 10 min before ghrelin) did not prevent the ability of ghrelin (500 pmol kg(-1) min(-1)) to shorten MMC cycle time.
CONCLUSIONS AND IMPLICATIONS
Obestatin has little ability to modulate rat GI motility.
Collapse