BEHAVIORALLY CONDITIONED EFFECTS OF CYCLOSPORINE-A ON THE IMMUNE-SYSTEM OF RATS - SPECIFIC ALTERATIONS OF BLOOD LEUKOCYTE NUMBERS AND DECREASE OF GRANULOCYTE FUNCTION

Immunosuppression induced by Cyclosporine A (CsA) can be behaviorally conditioned. It is unknown, however, whether a taste aversion paradigm using CsA. as an unconditioned stimulus (UCS) induces alterations of blood leukocyte numbers and function. Results obtained by three-colour flow cytometry and granulocyte chemiluminescence response demonstrate that in conditioned rats, absolute numbers of lymphocyte subsets, inc luding B, CD8(+) T cells and CD4(+) naive and memory T cells, and gran ulocyte numbers and function were significantly decreased. In contrast to the conditioned response, CsA treatment alone increased lymphocyte numbers and did not affect granulocyte function. Thus, our data demon strate that behaviorally conditioned CsA effects can be monitored in t he blood. In addition, results indicate that the CNS mediates the beha viorally conditioned immunosuppression by reducing the availability an d function of granulocytes and lymphocytes. (C) 1998 Elsevier Science B.V. All rights reserved.