Opioid peptides, receptors, and immune function.
The studies have clearly demonstrated that binding sites for opioid peptides, beta-endorphin, and methionine-enkephalin exist on T lymphocytes. beta-Endorphin appears to be immunodepressant, whereas methionine-enkephalin is immunostimulant. Both in vitro and in vivo studies have shown that methionine-enkephalin can influence some immune functions. Since in vitro modification of immune function requires very low concentrations, it is reasonable to believe that methionine-enkephalin plays a physiological role in the immune system. Although not well established, methionine-enkephalin appears to activate T lymphocytes via opioid receptors and triggers a series of intracellular signals leading to the activation of receptors for interleukin-2 (IL-2), OKT10, and active sheep T red blood cell receptors. Methionine-enkephalin enhances the activity of NK cells and induces the production of IL-2, which in turn may recruit and activate other T-cell subsets like CD3 and CD4. Methionine-enkephalin also enhances mitogen-induced proliferation of lymphocytes. Since preliminary studies with methionine-enkephalin in ARC patients have provided beneficial effects by the improvements in their symptoms, it will be worthwhile to extend these observations to a larger number of patients with ARC and AIDS. Finally, it appears that some endogenous opioid peptides and their analogs, in addition to methionine-enkephalin, may provide therapeutic benefits not only in ARC and AIDS but also in other immunodeficient states.
Bhargava
H N
HN
Department of Pharmacodynamics, College of Pharmacy, University of Illinois, Chicago 60612.
D000163:Acquired Immunodeficiency Syndrome / Q000097:blood / Q000276:immunology*; D000818:Animals; D000917:Antibody Formation; D001665:Binding Sites; D004744:Enkephalin, Methionine / Q000276:immunology* / Q000378:metabolism; D006556:Heroin Dependence / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D009021:Morphine Dependence / Q000276:immunology* / Q000378:metabolism; D009294:Narcotics / Q000276:immunology* / Q000378:metabolism; D011957:Receptors, Opioid / Q000276:immunology* / Q000378:metabolism
D009294:Narcotics; D011957:Receptors, Opioid; D004744:Enkephalin, Methionine