The scientists from Colombia have discovered neurons specialized in the brains of mice that order animals to no longer eat.
The brain cells that tell you not to eat photo: Shuterstock
Although it is known that many brain feeding circuits play a role in monitoring food consumption, neurons known in these circuits do not make the final decision to stop eating a meal.
Newly identified neurons, a new element of these circuits, are located in the brain trunk, the oldest part of the vertebrate brain. Their discovery could lead to new treatments for obesity, according to the researchers.
“These neurons are different from any other neuron involved in regulating satiety. Other neurons in the brain are usually limited to the detection of foods inserted in the mouth, how food fills the intestine or nutrition from food. The neurons I found are special by the fact that they seem to integrate all this different information and even more.“says Alexander Nectow, a research and surgeon of Colombia University, who led the research.
A new unicellular technique reveals neurons
The decision not to eat is a familiar phenomenon. “It happens every time we sit down to have a meal: at one point, as we eat, we begin to feel tired, then we feel more and more tired, and then we reach a point where we think it is sufficient”, says Dr. Nectow.
Other researchers have previously located the decision-making cells in the brainstem, but the tracks stopped there.
Also, the researchers used a new monocellular technique that makes it possible to enter a region of the brain and distinguish the different types of cells that have been difficult to distinguish from each other.
“This technique – spatially solved molecular profiling – allows you to see the cells where they are in the brain trunk and how their molecular composition looks. “says Dr. Nectow.
During the profile of a region of the brain trunk known for processing complex signals, the researchers observed previously unrecognized cells that had characteristics similar to other neurons involved in regulating appetite.
Neurons follow each bite
To see how the neurons influence the diet, the researchers designed the neurons so that they can be activated and disabled, by the researcher, with the help of light.
When neurons were activated by light, the mice ate much less. The intensity of the activation determined how quickly the animals stopped eating. “Interestingly, these neurons do not only signal an immediate stop; They help mice to gradually slow down food ”says Dr. Chowdhury.
The researchers found that neurons were silent by a hormone that increases the appetite and activated by a GLP-1 agonist, a class of drugs now popular for treating obesity and diabetes. These experiments found that these entries helped the neurons to follow each bite taken by mice.
“In essence, these neurons can smell food, see food, feel food in the mouth and intestine and interpret all intestinal hormones that are released in response to food. And finally uses all this information to decide when it is sufficient“Says Dr. Nectow.
Although specialized neurons were found in mice, Dr. Nectow says that their location in the brain trunk, a part of the brain that is essentially the same in all vertebrates, suggests that people have the same neurons.
“We believe that it is a new major entry point to understand what it means to be tired, how this happens and how it is used to conclude a meal. And we hope it could be used for therapies against obesity in the future ”concluded Alexander Nectow, a research and surgeon of Colombia University.
