Distribution of prostaglandin E receptors in the rat gastrointestinal tract.
OBJECTIVE
In order to study the role of prostaglandin in the regulation of the gastrointestinal functions, gene expression of prostaglandin receptors along the rat gastrointestinal tracts were investigated.


METHODS
Rats were used for the study. The combination of counterflow elutriation separation of mucosal cells and Northern blot analysis was used to detect the gene expression of prostaglandin receptors in gastrointestinal tracts.


RESULTS
In small intestine and colon, prostaglandin E2 EP1 and EP3 receptor mRNAs were mainly localized in the deeper intestinal wall containing muscle layers. EP4 receptor gene expression, on the other hand, was detected in the intestinal mucosal layer. In the stomach, EP1 mRNA was detected in gastric muscle layers, whereas EP3 and EP4 receptor gene expression was mainly present in the gastric mucosal layer containing epithelial cells. In gastric epithelial cells, parietal cells were found to have both EP3 and EP4 receptors. At lower concentrations, prostaglandin E2 inhibited gastric acid secretion by parietal cells probably through EP4 receptors. At higher concentrations, however, it stimulated it. On the other hand, mucous cells possessed only EP4 receptor mRNA.


CONCLUSIONS
Thus, it is suggested that prostaglandin E2 modulates gastrointestinal functions through at least three different prostaglandin receptors (EP1, EP3, and EP4), each of which has a distinct contribution in the gastrointestinal tract.
Ding
M
M
Department of Medicine, Kobe University School of Medicine, Japan.
Kinoshita
Y
Y
Kishi
K
K
Nakata
H
H
Hassan
S
S
Kawanami
C
C
Sugimoto
Y
Y
Katsuyama
M
M
Negishi
M
M
Narumiya
S
S
Ichikawa
A
A
Chiba
T
T
D000632:Aminopyrine / Q000378:metabolism / Q000493:pharmacokinetics; D000818:Animals; D015152:Blotting, Northern; D002250:Carbon Radioisotopes; D003106:Colon / Q000737:chemistry / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004064:Digestive System / Q000737:chemistry / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology*; D016620:Enprostil / Q000494:pharmacology; D005753:Gastric Mucosa / Q000378:metabolism; D007413:Intestinal Mucosa / Q000737:chemistry / Q000378:metabolism; D007422:Intestines / Q000737:chemistry; D008297:Male; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018078:Receptors, Prostaglandin E / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D058306:Receptors, Prostaglandin E, EP1 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013270:Stomach / Q000737:chemistry
D002250:Carbon Radioisotopes; D018076:DNA, Complementary; C545637:Ptger1 protein, rat; C545649:Ptger3 protein, rat; C545652:Ptger4 protein, rat; D018078:Receptors, Prostaglandin E; D058306:Receptors, Prostaglandin E, EP1 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D000632:Aminopyrine; D012313:RNA; D000242:Cyclic AMP; D016620:Enprostil; D015232:Dinoprostone