A study done on mice showed that the activation of neurons called CeAGA makes it possible to suppress pain in rodents.
“Many people think there’s a central area that relieves pain,” says neurobiologist Fan Wang, “which is why placebos work.” The scientific community has been looking for the location of this area. Professor Wang’s team may have found the answer. According to research published in Nature Neuroscience, it could be the amygdala, an area of the brain associated with emotions like fear and anxiety.
The role of CeAGA
“Most previous studies have focused on areas that are activated by pain,” he says. But there are so many areas that are responsible for pain that they all need to be inactivated to stop it. While only this area can eliminate pain by itself. To understand the role of the amygdala, Fan Wang and his team analyzed the effects of general anesthesia on neurons. They found that it activates a subset of inhibitory neurons in the amygdala, known as CeAGA neurons. These are linked to several other areas of the brain. By artificially stimulating pain in rats, they were able to create a map of the areas connected to the CeAGA neurons.
“Pain is a complex brain reaction,” says Fan Wang, “involving sensory, emotional, and automatic reactions of the nervous system.” Optogenetics, a technique that uses light to act on nerve cells, has enabled them to avoid these brain reactions in rats. For example, by activating the CeAGA neurons, the rats stopped licking their paws or cleaning their heads. “It’s radical,” stresses the researcher, “they stopped immediately!
A new class of painkillers
The researchers also discovered that these neurons are crucial for the effect of painkillers. For instance, low-dose ketamine, used as an analgesic, stimulates them. However, the effectiveness of Ketamine is nulled when these neurons are inactivated. The Fan Wang team now wants to continue its research to develop a treatment that can only activate CeAga neurons. By being able to do this it would be possible to come up with a new class of pain killers.