Growth Hormone Secretagogue Receptors in Rat and Human Gastrointestinal Tract and the Effects of Ghrelin

Dass, N. B., Munonyara, M., Bassil, A. K., Hervieu, G. J., Osborne, S., Corcoran, S., Morgan, M. and Sanger, G. J. (2003) Growth Hormone Secretagogue Receptors in Rat and Human Gastrointestinal Tract and the Effects of Ghrelin. Neuroscience, 120 2: 443-453. doi:10.1016/S0306-4522(03)00327-0


Author Dass, N. B.
Munonyara, M.
Bassil, A. K.
Hervieu, G. J.
Osborne, S.
Corcoran, S.
Morgan, M.
Sanger, G. J.
Title Growth Hormone Secretagogue Receptors in Rat and Human Gastrointestinal Tract and the Effects of Ghrelin
Journal name Neuroscience   Check publisher's open access policy
ISSN 0306-4522
Publication date 2003-01-01
Year available 2003
Sub-type Article (original research)
DOI 10.1016/S0306-4522(03)00327-0
Open Access Status DOI
Volume 120
Issue 2
Start page 443
End page 453
Total pages 11
Place of publication Oxford
Publisher Pergamon
Language eng
Subject 110905 Peripheral Nervous System
Abstract The peptide hormone ghrelin is known to be present within stomach and, to a lesser extent, elsewhere in gut. Although reports suggest that gastric function may be modulated by ghrelin acting via the vagus nerve, the gastrointestinal distribution and functions of its receptor, the growth hormone secretagogue receptor (GHS-R), are not clear and may show signs of species-dependency. This study sought to determine the cellular localisation and distribution of GHS-R-immunoreactivity (-Ir) using immunofluorescent histochemistry and explore the function of ghrelin in both human and rat isolated gastric and/or colonic circular muscle preparations in which nerve-mediated responses were evoked by electrical field stimulation. The expression of GHS-R-Ir differed to a greater extent between species than between gut regions of the same species. Both the human and rat gastric and colonic preparations (n=3 each) expressed GHS-R-Ir within neuronal cell bodies and fibres, cells associated with gastric glands and putative entero-endocrine and/or mast cells. Smooth muscle cells and epithelia were devoid of GHS-R-Ir and only rat preparations expressed GHS-R-Ir on nerve fibres associated with the muscle layers. GHS-R-Ir was fully competed in all cases in pre-adsorption studies and antiserum specificity was confirmed using a cell line transiently expressing the rat GHS-R. In rat isolated forestomach circular muscle, ghrelin 0.1–10 μM had no effect on smooth muscle tension but concentration-dependently facilitated the amplitude of contractions evoked by excitatory nerve stimulation (n=4–7; P<0.05 for each concentration versus vehicle; n=18). When examined under similar conditions, in both rat distal colon (n=4–6, P>0.05 each) and human ascending (n=3) and sigmoid (n=1) colon, these concentrations of ghrelin were without effect (P>0.05 each). The data suggest that ghrelin has the potential to profoundly affect gastrointestinal functions in both species and at least one of these functions is to exert a gastric prokinetic activity. Moreover, we suggest that this activity of ghrelin is mediated via the enteric nervous system, in addition to known vagus nerve-dependent mechanisms.
Keyword enteric nervous system
gastric fundus
sigmoid colon
gastro prokinetic
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Queensland Brain Institute Publications
 
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