| Theme | The Role of Receptors in Gastrointestinal Functions | |
|---|---|---|
| Title | Dopamine Receptors | |
| Publish Date | 2000/04 | |
| Author | Akihito Nagahara | Department of Gastroenterology, Juntendo University, School of Medicine |
| [ Summary ] | It is known that dopamine receptors have 5 receptor subtypes, which are known as D1, D2, D3, D4 and D5 receptor subtypes. D1 and D2 receptor subtypes play important roles in the gastrointestinal tract. Dopaminergic compounds act on the gastrointestinal tract through these dopamine receptors. The role of dopamine agonists in the gastrointestinal tract, through dopamine receptors introduces many events;attenuate gastric motility, increased gastrointestinal blood flow and improved gastric mucosal microcirculation, reduced gastric acid secretion and increased gastroprotective activity. Moreover, significant alterations of dopamine receptors in gastric and colon carcinoma are reported. Dopamine receptor agonists also regulate mucosal proliferation, which may have a correlation with carcinogenesis. In widely clinical use, D2 receptor antagonists, such as domperidone, sulpiride and metoclopramide improve cases of nausea, gastrointestinal dysmotility and gastroduodenal ulcers through blocking D2 receptors, which are located in the chemoreceptor trigger zone in the brain and in the stomach. |
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