Nausea and Vomiting (N&V) are essential physical process required to protect the body from ingestion of potentially harmful substances. However in a disease state the reflex is often hypersensitive leading to prolonged emesis and concomitant nausea. N&V is commonly associated with many chemotherapeutic drugs which the body identifies as potentially toxic.
The process of N&V is initiated by the chemoreceptor trigger zone (CTZ) which is responsible for detecting emetic agents in the blood. The CTZ has two main receptors, specifically dopamine type 2 (D2) and serotonin 5-HT3. Emetic agents that activate these receptors cause the physiological process of vomiting.
This image is a simplification for website aesthetics only. For more information please refer to the clinical studies referenced below.
In response to a noxious stimulus specific neurotransmitters are released in the Chemoreceptor Trigger Zone (CTZ), one of which is serotonin. Serotonin binds to the 5HT3A receptor at the CTZ and initiates an emetic response.
Cannabidiol is an allosteric inhibitor of the 5-HT3 receptor meaning that its binding causes a conformational change which, in turn, reduces the ability of serotonin to bind to the CTZ and cause emesis.
The endocannabinoid system is thought to control the release of newly synthesized serotonin within the presynaptic neuron. By modulating the release of this neurotransmitter endocannabinoid activation is suggested to reduce nausea and vomiting.
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Manzanares, J., Julian, M. D., & Carrascosa, A. (2006). Role of the cannabinoid system in pain control and therapeutic implications for the management of acute and chronic pain episodes. Current neuropharmacology, 4(3), 239.