The brain cells responsible for retching have been identified in mice: “turning them off” could help find drugs, for example, to combat vomiting induced by chemotherapy or other treatments
Vomiting is not a pleasure, but it is certainly a necessity: when we come into contact with food, liquids or other substances that could harm us, the body reacts in this way to eliminate them. And everything is actually “born” in the brain, as demonstrated by research conducted on mice by researchers from the National Institute of Biological Sciences of Beijing in China: the input to retching comes from specific neurons of the brainstem and “silence” them with specific drugs it could help fight vomiting induced for example by chemotherapy or other treatments.
Research
The researchers studied mice exposed to enterotoxin A, a bacterial toxin produced by Staphylococcus aureus, to reconstruct the signals that from the digestive tract, when it comes into contact with contaminated food or drinks, lead to nausea and vomiting. The mice do not vomit but have well-defined retching, with simultaneous contractions of the diaphragm and abdominal muscles similar to those observed for example in dogs when they vomit; the mechanism is therefore similar and so what happens in the intestine and brain of animals exposed to the toxin was analyzed in detail, first of all discovering that qWhen something “unwelcome” arrives, specific intestinal cells produce serotonin, a mediator that binds to receptors on sensory neurons also found in the gut. From here, the message passes to the brain via the vagus nerve.
It is decided in the brain
The signal path ends up particular neurons which are located in the dorsal vagal complex of the brain stem, a structure at the base of the brain: these cells, called Tac+DVC, they would be directly responsible for the vomiting because inactivating them the retching disappears or almost. Confirmation came by injecting mice with doxorubicin, a chemotherapy which often induces nausea and vomiting: the animals normally after taking the drug have obvious retching, but if the Tac+DVC neurons are inactivated the symptoms are greatly reduced. Something similar also happens by reducing the production of serotonin by intestinal cells and this, as author Peng Cao said: “It helps explain why many antiemetics that have been shown to be effective are serotonin receptor blockers. Better understood the cellular and molecular mechanisms of nausea and vomiting
could help identify better and even more targeted drugs» concludes the researcher.
January 5, 2023 (change January 5, 2023 | 3:55 pm)
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