Chemoreceptor Trigger Zone

The chemoreceptor trigger zone (CTZ) is a group of neurons in the area postrema of the medulla. Once stimulated, it activates the vomiting center, which is also located in the medulla, thereby causing emesis.

  • The CTZ is sensitive to a variety of chemical stimuli.
  • Syrup of ipecac (synonym ipecacuanha) and apomorphine are direct stimulators of the CTZ.
  • Clinically they are used to provoke emesis after oral ingestion of a poison.
  • The CTZ is also stimulated by other drugs, e.g. cardiac glycosides, morphine (opioid system) and antineoplastic agents.

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