PUBLICATION

Identification of genes for the ghrelin and motilin receptors and a novel related gene in fish, and stimulation of intestinal motility in zebrafish (Danio rerio) by ghrelin and motilin

Authors
Olsson, C., Holbrook, J.D., Bompadre, G., Jönsson, E., Hoyle, C.H., Sanger, G.J., Holmgren, S., and Andrews, P.L.
ID
ZDB-PUB-090109-2
Date
2008
Source
General and comparative endocrinology   155(1): 217-226 (Journal)
Registered Authors
Keywords
Danio rerio, Erythromycin, Ghrelin, Intestinal motility, Motilin, Pufferfish, Zebrafish
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Cloning, Molecular
  • Electric Stimulation
  • Erythromycin/pharmacology
  • Female
  • Fishes/genetics*
  • Gastrointestinal Motility/drug effects*
  • Ghrelin/pharmacology*
  • Ghrelin/physiology
  • Humans
  • Male
  • Molecular Sequence Data
  • Motilin/pharmacology*
  • Motilin/physiology
  • Phylogeny
  • Receptors, Gastrointestinal Hormone/genetics*
  • Receptors, Ghrelin/genetics*
  • Receptors, Neuropeptide/genetics*
  • Sequence Homology
  • Zebrafish/genetics
  • Zebrafish/physiology*
PubMed
17582410 Full text @ Gen. Comp. Endocrinol.
Abstract
In mammals ghrelin has a diverse range of effects including stimulation of gut motility but although present in teleost fish its effects on motility have not been investigated. The present study used bioinformatics to search for fish paralogues of the ghrelin receptor and the closely related motilin receptor, and investigated the effects of ghrelin and motilin on gut motility in zebrafish, Danio rerio. Fish paralogues of the human ghrelin and motilin receptor genes were identified, including those from the zebrafish. In addition, a third gene was identified in three species of pufferfish (the only fish genome completely sequenced), which is distinct from the ghrelin and motilin receptors but more closely aligned to these receptors relative to other G-protein coupled receptors. Immunohistochemistry demonstrated strong ghrelin receptor-like reactivity in the muscle of the zebrafish intestine. In isolated intestinal bulb and mid/distal intestine preparations, ghrelin, motilin, and the motilin receptor agonist erythromycin all evoked contraction; these responses ranged between 9% and 51% of the contractions evoked by carbachol (10(-6) M). There were some variations in the concentrations found to be active in the different tissues, e.g., whereas motilin and rat ghrelin caused contraction of the intestinal bulb circular muscle at concentrations as low as 10(-8) M, human ghrelin (10(-8) to 10(-6) M) was without activity. Neither ghrelin (10(-7) M) nor erythromycin (10(-5) M) affected the contractions evoked by electrical field stimulation. The results suggest that both ghrelin and motilin can regulate intestinal motility in zebrafish and most likely other teleosts, and are discussed in relation to the evolution of these regulatory peptides.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping