The area postrema is a small paired bump in the floor of the fourth ventricle at its lowest point. It is a circumventricular organ, meaning the blood-brain barrier is absent there, so it can sample toxins and hormones directly from the blood. It contains the chemoreceptor trigger zone that triggers vomiting.
| Location | Caudal end of the floor of the fourth ventricle, at the obex, in the dorsal medulla |
|---|---|
| Parts |
|
| Connections |
|
| Blood Supply | Posterior inferior cerebellar artery |
Detects circulating toxins, drugs and hormones and triggers nausea and vomiting, and helps regulate appetite, fluid balance and blood pressure.
Chemotherapy, opioids and many other drugs cause nausea by stimulating dopamine (D2) and serotonin (5-HT3) receptors here, which is why antiemetics such as ondansetron and metoclopramide work. Area postrema syndrome, with persistent hiccups, nausea and vomiting, is a characteristic presentation of neuromyelitis optica spectrum disorder.
Unexplained, persistent nausea, vomiting or hiccups from an inflammatory lesion of the area postrema, classically in neuromyelitis optica spectrum disorder.
Nausea triggered by cancer drugs stimulating receptors in the chemoreceptor trigger zone.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
