MECHANISMS OF CONDITIONED IMMUNOMODULATION

This article presents some recent work from our laboratory indicating that multiple physiological systems play a role in conditioned immunom odulation. The first study shows that naltrexone, but not N-methylnalt rexone, blocks the suppressive effects of an aversive conditioned stim ulus on Con-A-induced proliferation and natural killer cell activity o f splenic lymphocytes. This Ending indicates that central opioid activ ity is involved in the conditioned effects. The second study shows tha t the beta-adrenergic antagonists atenolol and ICI-118,551 block the s uppressive effects of an aversive conditioned stimulus on Con-A-induce d proliferation, but have no effect on natural killer cell activity. T his result indicates the involvement of the adrenergic system in a sub set of the conditioned effects. Collectively, these experiments provid e evidence that both the opioid system and the sympathetic nervous sys tem are involved in conditioned immunomodulatory changes elicited by a n aversive conditioned stimulus.