V. Ramirezamaya et al., INSULAR CORTEX LESIONS IMPAIR THE ACQUISITION OF CONDITIONED IMMUNOSUPPRESSION, Brain, behavior, and immunity, 10(2), 1996, pp. 103-114
Conditioned immunosuppression can be readily obtained in animals by as
sociating a taste with an immunosuppressive drug. On subsequent exposu
re to the conditioned taste, the animals show an attenuated immune res
ponse and also exhibit a conditioned taste aversion. It has been estab
lished that insular cortex lesions disrupt the acquisition of conditio
ned taste aversion. The effect of NMDA-induced lesions in either the i
nsular cortex or the parietal cortex of male Wistar rats was evaluated
in the acquisition of conditioned immunosuppression in two experiment
s. Unlesioned control rats showed the conditioned immunosuppressive re
sponse after reexposure to the taste, as indicated by lower hemaggluti
nating titers to sheep red blood cells in the first experiment and by
a decreased IgM production to ovalbumin, measured by ELISA, in the sec
ond experiment. Insular cortex-lesioned rats did not show the conditio
ned immunosuppression in either experiment, while parietal cortex lesi
ons and the sham-lesioned animals presented a clear decrease of hemagg
lutinating titer and a low IgM production. The insular cortex lesions
did not affect the normal immune response, showing normal hemagglutina
ting titers and IgM production when compared to nonconditioned control
s. The immunosuppressive action of cyclophosphamide also remained unal
tered. In conclusion, these results show that the insular cortex is es
sential for the acquisition of conditioned immunosuppression. (C) 1996
Academic Press, Inc.