RESUMO
Food allergy accounts for a great number of reactions leading to diminished quality of life in western countries. There has been an abundance of reports of behavioral changes, as well as psychiatric conditions associated with food allergy over the past decades. Most of this field inspired little medical attention for its lack of a solid scientific ground. We review the literature on the association of food allergy and brain activity, leading to changes in emotion and behavior. Moreover, we describe an experimental paradigm employed to dissect the biological relevance of this association. Mice allergic to ovalbumin avoid a palatable sweet solution in order to escape contact with antigen. This choice is associated with increased levels of anxiety, compatible with a conflicting situation. These responses are associated with increased activity in brain areas associated with emotional and affective behavior, which are also important for anxiety and stress responses. Higher levels of corticosterone accompany these changes in behavior. These responses are mediated by specific antibodies and prevented by depletion or immunological tolerance. They are also partially mediated by C-sensitive afferents and mast cells. Far from anecdote, neural repercussions of food allergy should be considered when planning a therapeutic strategy in affected individuals.
Assuntos
Hipersensibilidade Alimentar/imunologia , Tonsila do Cerebelo/imunologia , Tonsila do Cerebelo/metabolismo , Animais , Anticorpos/imunologia , Anticorpos/metabolismo , Encéfalo/metabolismo , Hipersensibilidade Alimentar/metabolismo , Humanos , Hipotálamo/imunologia , Hipotálamo/metabolismo , Mastócitos/imunologia , Mastócitos/metabolismo , Fibras Nervosas/imunologia , Fibras Nervosas/metabolismo , Neuroimunomodulação , Transdução de SinaisRESUMO
OBJECTIVE: This study was designed to evaluate the role of c-sensitive fibers in the establishment of immune-induced flavor aversion in mice. METHODS: Mice were treated neonatally with capsaicin in order to destroy c-sensitive fibers; after such treatment, adult animals, immunized or not with ovalbumin, were submitted to a two-bottle preference test, with a choice between water and a sweetened egg white solution. RESULTS: Neonatal capsaicin treatment was unsuccessful in preventing the development of immune-induced aversion to the sweetened solution containing the antigen. Nonetheless, amongst immunized mice, those which had been previously treated with capsaicin showed a significant increment in the preference for the sweetened egg white solution. Furthermore, our data showed that neonatal capsaicin treatment did not interfere with either IgG1 or IgE production. CONCLUSION: The present results suggest that c-sensitive fibers have a role in the transmission of the signals generated by this immune response to the central nervous system, thus contributing to the development of a flavor aversion in mice.