Chemoreceptor trigger zone – central emetic circuitry (CTZ)

The Chemoreceptor Trigger Zone (CTZ) is a neuroanatomical structure located in the area postrema of the medulla oblongata, functioning as a key sensory organ for the central emetic circuitry (StatPearls, 2023). Because it lies outside the blood-brain barrier, the CTZ can detect circulating toxins, metabolic products, and drugs in the blood and cerebrospinal fluid (NCBI, 2022). Upon activation, it transmits signals to the nucleus tractus solitarius and the central pattern generator (vomiting center) to initiate the emetic reflex. This circuitry is characterized by a high density of receptors, including serotonin 5-HT3, dopamine D2, neurokinin-1 (NK1), and histamine H1 receptors, which are the primary molecular targets for antiemetic drugs (PubMed, 2021). Clinical management of conditions like chemotherapy-induced nausea and vomiting (CINV) and postoperative nausea and vomiting (PONV) relies heavily on modulating these pathways (NIH, 2023).

Other names

Area postremaVomiting centerEmetic centerCentral emetic pathwayPostrema-NTS-CPG axis

Antagonism of specific neurotransmitter receptors (5-HT3, D2, NK1, H1, or M1) within the area postrema and nucleus tractus solitarius to block the transmission of emetic stimuli to the central pattern generator (StatPearls, 2023).