Vagus nerve receptors may be key to controlling inflammation

Researchers have identified a receptor on the mouse vagus nerve that helps control inflammation.

To Grace Wade

Specific receptors on the vagus nerve help detect and control inflammation in mice. If the same holds true for humans, these receptors could be targets for future treatments for inflammatory conditions such as rheumatoid arthritis and multiple sclerosis.

“Inflammation is our body’s response to injury and infection,” says Kevin Tracy of the Feinstein Institute for Medical Research in New York. Left unchecked, this reflex can work against us because excessive inflammation damages cells and contributes to chronic disease. will be done,” he says.

It is well known that the brain sends signals to control inflammation through the vagus nerve, but how the brain knows when to stop inflammation was previously unknown. I didn’t know what it was,” says Tracy.

To determine this, he and his colleagues studied eight mice. Half of them had been genetically engineered to lack specific types of receptors on the vagus nerve that are sensitive to several inflammatory molecules.

Proteins called cytokines are a major cause of inflammation, so researchers injected mice with a class of cytokines known to induce changes in body temperature. They found that genetically engineered mice maintained body temperature, while others developed hypothermia. This suggests that the body needs vagus nerve receptors to detect inflammation.

The team then injected toxic molecules into another group of 19 mice to induce a cytokine storm, in which cytokine overproduction causes life-threatening inflammation. They used optogenetics, a technique that uses light to turn cells on and off, to activate vagus nerve receptors in 10 of these mice. Mice produced, on average, half as many cytokines as mice in which these receptors were not activated, and suffered significantly less inflammatory damage.

Taken together, these findings indicate that these specific receptors on the vagus nerve not only detect inflammation, but suppress it by signaling to the brain when it needs to stop the inflammatory response. is showing.

Tracey says these findings are important for two reasons. The first is to provide “new ways to think about how the brain and nervous system interact with the immune system to control the consequences of infection and injury.” The receptor could lead to the development of new treatments for people with chronic diseases characterized by excessive inflammation.

For example, clinical trials have shown that stimulating the vagus nerve with electrical pulses can reduce symptoms and even slow the progression of diseases such as epilepsy, inflammatory bowel disease, and multiple sclerosis. These findings raise the possibility of developing hyperselective vagus nerve stimulants that act only on receptors known to control inflammation, potentially improving treatment outcomes, he said. Says.

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