Chemoreceptor trigger zone of medulla oblongata (CTZ)

The Chemoreceptor trigger zone of the medulla oblongata is a small, specialized neuroanatomical area located within the area postrema on the floor of the fourth ventricle, outside the blood-brain barrier[2][3][1]. It is highly vascularized and populated by various cell types, including astrocytes and neurons with direct access to blood-borne substances[1]. Its primary function is to detect toxins and drugs circulating in the blood and cerebrospinal fluid and relay emetogenic signals to the adjacent vomiting center, initiating the physical act of vomiting. The CTZ contains multiple neurotransmitter receptors (including dopamine D2, serotonin 5-HT3, histamine H1, acetylcholine, substance P (NK-1), and opioid receptors), which are the targets of antiemetic drugs. This system serves as a crucial protective mechanism to expel potentially harmful substances before they can exert systemic toxicity[2][3][5][1].

Other names

Chemoreceptor trigger zoneCTZarea postremacentral emetic chemoreceptor apparatus

Blockade of neurotransmitter receptors in the CTZ (D2, 5-HT3, NK-1, H1, muscarinic receptors); Inhibition of signal relay to vomiting center, thereby preventing coordinated emetic motor response.