Expression of endothelin receptors in the gastric mucosa of portal hypertensive rats.
BACKGROUND
Portal hypertensive gastropathy is an abnormal circulatory state in gastric mucosa with vascular dilatation due to portal hypertension. The aim of the present study was to evaluate expression of endothelin receptors and their roles in the portal hypertensive gastric mucosa.


METHODS
Portal hypertensive rats were generated by staged portal vein occlusion. Expression of endothelin-A receptor and endothelin-B receptor mRNA was examined by reverse transcriptase-polymerase chain reaction, and protein were examined by immunohistochemistry. The changes of mucosal microcirculation by endothelin receptor antagonists were measured with in vivo microscope.


RESULTS
Expression of endothelin-A receptor mRNA was increased significantly in portal hypertensive rats in comparison with sham-operated control rats (P < 0.05). There was no significant difference between the two groups in endothelin-B receptor mRNA expression. Vessels of the gastric mucosa were dilated, and intravessel blood flow was increased significantly in the portal hypertensive group (P < 0.05). Diameters of mucosal vessels and blood flow were increased significantly by endothelin-A receptor antagonist (BQ-485) in the portal hypertensive rats. Endothelin-B receptor antagonist (IRL-1038) had no significant effect on mucosal microcirculation.


CONCLUSIONS
These data suggest that increased expression of endothelin-A receptor in the portal hypertensive gastric mucosa may be related to the regulation of gastric microcirculation.
Kai
Seiichiro
S
Department of Surgery I, Oita University Faculty of Medicine, Oita, Japan. kaisei@med.oita-u.ac.jp
Bandoh
Toshio
T
Ohta
Masayuki
M
Matsumoto
Toshifumi
T
Tominaga
Masayuki
M
Kitano
Seigo
S
D000818:Animals; D001381:Azepines / Q000494:pharmacology; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D016232:Endothelins / Q000494:pharmacology; D005753:Gastric Mucosa / Q000098:blood supply / Q000378:metabolism*; D006975:Hypertension, Portal / Q000150:complications / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D017082:Portal Pressure / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A / Q000378:metabolism*; D044023:Receptor, Endothelin B / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013272:Stomach Diseases / Q000209:etiology / Q000503:physiopathology
D001381:Azepines; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D016232:Endothelins; D009842:Oligopeptides; D010446:Peptide Fragments; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; C083116:BQ 485; C077420:Cys(11)-Cys(15)-endothelin-1 (11-21)