Immune-induced flavor aversion in mice:: Modification by neonatal capsaicin treatment

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. Copyright (C) 2001 S. Karger AG, Basel.