[Localization and expression of dopamine receptors in stomach and duodenum in rats].
Dopamine is an important neurotransmitter which may contribute to the regulation of gastrointestinal function, but its mechanism remains elusive.


OBJECTIVE
The existence, localization and expression of dopamine receptor mRNAs in rat stomach and duodenum were examined by in situ hybridization.


METHODS
The oligonucleotide probes were selected and synthesized according to the previous work. All the probes were labelled with alpha S35dATP using the terminal deoxynucleotide transferase, then were hybridized with the frozen, fixed preparation of rat stomach and duodenum. The density of silver granules were counted and analyzed by the image analysis computer system.


RESULTS
It was found that all five subtypes of dopamine receptor mRNAs existed in the stomach and duodenum with greatly different expression. The distribution of dopamine mRNAs in the stomach were mainly localized in the lamina propria near the lamina muscularis mucosae and parallel to the longitudinal axis of the tract. Whereas, all five MRNAs were spread over the entire layer of the duodenal mucosa. With the image analysis system, abundant expressing levels of D5 and D4 mRNAs were documented unexpectedly.


CONCLUSIONS
All these results suggest that dopamine produced its effect via dopamine receptors especially D5 subtype and D4 receptor might be act as a modulator.
Deng
X
X
Department of Gastroenterology, Third Hospital of Beijing Medical University.
Zheng
Z
Z
Ye
S
S
D000818:Animals; D004386:Duodenum / Q000378:metabolism*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000032:analysis / Q000096:biosynthesis*
D011954:Receptors, Dopamine