Nausea is an uneasiness or discomfort of the upper stomach that often precedes vomiting. An extremely common symptom of many conditions, nausea can develop for a wide variety of reasons. The body’s endocannabinoid system, which is instrumental in managing various processes, is responsible for regulating the presence and intensity of nausea.
Vomiting plays an important defensive role in preventing the digestion of harmful substances. However, the sensitivity of the nausea reflex is low and can be activated easily. Medications, viral gastroenteritis and migraine are just some of the symptom’s potential causes. Anxiety and depression, or the feeling of disgust, can also cause nausea and vomiting.
While some serious conditions are associated with nausea, most causes of stomach discomfort are not serious. However, nausea and vomiting are uncomfortable and in some instances can prevent the consumption of much-needed medications, such as chemotherapy. In some cases, nausea and vomiting side effects can be so debilitating that they prevent patients from continuing with treatments.
The triggering of nausea and vomiting is handled by a special center in the brain – the area postrema of the dorsal vagal complex (DVC). The postrema responds to chemical inputs from medications and hormones, and then sends signals to the digestive system to either stimulate or suppress nausea. If you consume a toxin, an illness-inducing food, or a nausea-causing medicine for example, the postrema responds by triggering nausea. The postrema also helps address any conflicts in balance and vision that can cause motion sickness.
Considerable evidence indicates that the endocannabinoid system plays a significant role in the regulation of nausea and vomiting. The endocannabinoid system is a signaling network that regulates an array of body processes. Endogenous ligands called cannabinoids are synthesized on demand to interact with the system’s cannabinoid receptors — CB1 and CB2 — to stimulate a chemical response that helps keep our systems in balance.
CB1 receptors have been found in areas of the brain involved in the nausea response, including the DVC. Cannabinoids that are agonists of these CB1 receptors, meaning they bind directly to the receptors, have been found to effectively suppress nausea and vomiting. Inverse agonists of the receptor, which bind to CB1 but induce an opposite response, have been shown to encourage the symptoms.
Since the discovery of the endocannabinoid system and its receptors, scientists have investigated how modulating the system could be beneficial for managing certain conditions and symptoms, including nausea. The studies that have been done indicate that supplementing with plant-derived cannabinoids like tetrahydrocannabinol (THC) and cannabidiol (CBD) helps to suppress nausea symptoms. For those who develop nausea from much-needed medications, like chemotherapy, incorporating cannabinoids into their regimen may help them undergo treatments more comfortably.