Opioids in Immunologic Processes

The immune response consists of a number of concerted events including recognition processing of foreign antigen proliferation differentiation of responder cells the production of peptide and protein mediators for amplification and regulation of the response. It is clear that the immune system is not isolated autonomous; rather it constitutes one-third of a triad of communicative networks (including the nervous system endocrine system) which are intimately interactive. A wealth of information is now available demonstrating the control the brain exercises over the immune system. The ability of stressful situations to produce dramatic alterations in immune status is indicative of this control exerted by the brain via neuronal pathways or modulation of endocrine outflow. The immune system can also affect brain function, as demonstrated by elevations in brain neurotransmitter levels (Barneound et al. 1988) and enhanced electrical activity in certain brain nuclei (Saphier et al. 1987) following activation of the immune system subsequent to bacterial infection. Within this neuroendocrine-immune axis feedback loops have been identified with immune cell products (e.g. interleukin-1) capable of stimulating the hypothalamo-pituitary-adrenal axis (BERNTON et al. 1987) leading to the production of glucocorticoids which are well-known immunomodulators.