THE RELEVANCE OF OPIOIDS AND OPIOID RECEPTORS ON IMMUNOCOMPETENCE ANDIMMUNE HOMEOSTASIS

Since the previous review on the role of opioids in the immune system, numerous investigative teams have contributed to the growing pool of information illustrating the tangible relationship between opioids and immune function, particularly as this association pertains to bacteri al and viral pathogens, In addition, the recent cloning of both neural - and immune-derived apioid receptors will ultimately facilitate the i dentification of molecular events that are responsible for the immunom odulatory effects that are mediated by receptor ligation, Specifically , the administration of opioids in vivo can potentially affect the imm une system either through direct interaction with receptors an the eff ector cells or indirectly, through the ligation of receptors found wit hin the central nervous system, This indirect routing is hypothesized to involve secondary pathways Including the hypothalamic pituitary adr enal (HPA) axis and the sympathetic nervous system ultimately resultin g in immunomodulation, Consequently, a portion of this review addresse s the recent data on leukocyte-derived opioid receptors and the potent ial immunoregulatory role relative to opioid receptors found within th e central nervous system, In addition, recent observations on the effe cts of opioids and immunocompetence is reviewed from both a molecular and cellular perspective, Finally, the consequence of opioid exposure on the competence of the host immune system to microbial pathogens is summarized.