title: Beta-endorphin and met-enkephalin stimulate human peripheral blood mononuclear cell chemotaxis.
abstract: The neuropeptides beta-endorphin and met-enkephalin are potent analgesics and have a broad spectrum of biologic activities including the recently described alterations of lymphocyte proliferation and antibody production. The current study demonstrates that beta-endorphin and met-enkephalin stimulate human mononuclear cell chemotaxis, as measured by the in vitro leading front assay for migration. The response to both beta-endorphin and met-enkephalin was bimodal, with peak activities occurring at 10(-12) M and 10(-8) M. The distance migrated in response to optimal concentrations of beta-endorphin or met-enkephalin was approximately 80% of that obtained with 10(-8) M formyl-methionyl-leucyl-phenylalanine (f-MLP) and was blocked by prior incubation with 10(-8) M naloxone. Removal of glass adherent cells resulted in a loss of the response to beta-endorphin. Quantitation of the number of cells responding to beta-endorphin showed that only about 50% as many cells responded to beta-endorphin as compared with f-MLP. Human neutrophils showed some migration in response to beta-endorphin and met-enkephalin, although the average optimal migration was less than 30% of that observed with 10(-8) M f-MLP. Studies of the in vivo infusion of beta-endorphin into the cerebral ventricle of the rat resulted in the immigration of macrophage-like cells and are consistent with the in vitro evidence for a chemotactic effect of beta-endorphin.
mesh_terms: D000818:Animals; D002469:Cell Separation; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004723:Endorphins / Q000008:administration & dosage / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D004805:Ependyma / Q000648:ultrastructure; D006801:Humans; D008264:Macrophages / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism; D044042:Receptors, Formyl Peptide; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D011956:Receptors, Cell Surface; D044042:Receptors, Formyl Peptide; D004744:Enkephalin, Methionine; D001615:beta-Endorphin