In allergic diseases such as hay fever, bronchial asthma, and atopic dermatitis, positive mental states have been shown to have a significant effect on symptoms and drug efficacy, but the biological mechanism remains unclear.In the study, mice were used to activate a neural network called the dopamine reward system in the brain, which controls positive emotions (motivation), in several ways, and analyzed its effect on allergic reactions.

　The center of the dopamine reward system is the ventral tegmental area (VTA) of the midbrain in the brain.In the experiment, VTA was activated in mice by the following three methods. (3) Artificial activation by the latest technology (DREADD) that manipulates the brain. (1) Natural activation by artificial sweetener mixed with drinking water. (2) Activation by injection of L-dopa, a precursor (material) of dopamine.In both cases, the magnitude of the urticaria reaction evoked on the skin of the mice was significantly reduced.This indicates that activation of the dopamine reward system in the brain has the effect of suppressing allergic reactions.

　The results of this study are the world's first findings that directly demonstrate that specific brain networks that produce positive mental states are closely linked to the immune system that causes allergies.It was suggested that in order to properly treat allergic patients and control their symptoms, it is important for them to maintain positive feelings at the same time as managing their daily lives and taking medication.

　This research was carried out by raising a part of the research funds by crowdfunding for the first time at the University of Yamanashi.

Paper information:[Allergy] Activation of the reward system ameliorates passive cutaneous anaphylactic reaction in mice