EXOGENOUS AND ENDOGENOUS OPIOIDS AS BIOLOGICAL RESPONSE MODIFIERS

Narcotic opioid compounds are among the most widely prescribed drug in terventions for individuals suffering pain. Among the unwarranted side effects of respiratory depression, constipation, and physical depende nce are the immunosuppressive qualities, particularly those which affe ct cell-mediated immunity. The immunosuppressive characteristics of op ioid narcotics (e.g., morphine) have recently come into focus with the advent of acquired immune deficiency syndrome (AIDS) and the putative causative agent, human immunodeficiency virus type 1 (HIV-1). Specifi cally, a vast reservoir of HIV-l-infected individuals exists among dru g abusers. Moreover, experimental evidence would suggest narcotic opio ids may increase viral load in infected individuals by modifying the c ellular machinery of activated leukocytes. Likewise, investigators hav e shown that opioids modify tumor growth and development. In this revi ew, a comparison between endogenous opioid peptides and exogenous opia tes on cell-mediated immunity and its relationship to viral infection and tumors is described.