“I feel good” is the message sent by neurons that detect caresses when an individual is gently touched or massaged on the skin. An American study has just identified thatthere is a type of neurons, without myelin and highly branched, specialized in detecting caresses in mice. The investigation, which today occupies the cover of the magazineNature, reveals that these cells generate a feeling of well-being when activated. Despite numerous physiological studies in this regard, this is the first time that sensory neurons have been identified in vivo that detect “pleasant” strokes.
The authors of the work, led by David Anderson, of the California Institute of Technology (CalTech), used a brush designed to simulate the type of caresses that rodents can feel and used it to brush the hairy hind legs of the mice.
Next, using neuroimaging techniques, they verifiedneurons that responded to the stimulus expressed the MRGPRB4 protein and lacked myelin fibers, a wrap that makes the nerve impulse travel faster. Furthermore, these “caress neurons” exclusively innervated the hairy skin through large branches. The work reveals that these neurons are activated by stroking the animal’s skin, but not by harmful stimulation, such as a pinch or pinch. Moreover, when applying these harmful stimuli, other neurons are activated – those that express the MRGPRD protein – that do not respond to caresses, according to the SINC agency.
In order tocheck the influence of petting on behavior, the authors developed a behavioral experiment in which they pharmacologically activated the neurons that detect caresses, and verified that this activation hadAnxiolytic and Positive Reinforcement Effects in Animals. According to the work, the results open a door to understand the function of this type of neurons during some social interactions such as social grooming, through self-stimulation or in other situations.
The authors say that more research will be needed to confirm whether there are neurons with similar properties in humans.
