title: Delta-opioid receptor antagonist inhibits immunomodulation by Met-enkephalin analogs.
abstract: The methionine-enkephalin (Met-enkephalin, Tyr-Gly- Gly-Phe-Met) analogs Tyr-D-Ala-Gly-MePhe-Met NHC(3)H(7)-iso (1) and Tyr-D-Ala-Gly-MePhe-Gly-NHC(3)H(7)-iso (2) have been shown to enhance human T cell proliferation in in vitro treatment. Their immunomodulatory activities were completely blocked by naloxone, an opioid antagonist. Now we demonstrate that a selective delta-opioid receptor antagonist, ICI-174,864, completely blocks enhancement of T cell proliferation by analogs (1) and (2). The T cell-stimulatory effect was only partially inhibited by the mu-receptor-selective antagonist, beta-funaltrexamine hydrochloride. The kappa-opioid receptor antagonist, nor-binaltorphimine dihydrochloride, showed no effect on T cell-proliferation stimulated by analogs (1) and (2). These observations suggest that analogs (1) and (2) of Met-enkephalin stimulate T cell proliferation predominantly via delta-opioid receptor present on T cells.
authors.affiliation: Department of Immunology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow, India. vksingh@sgpgi.ac.in
authors.forename: V K
authors.initials: VK
authors.lastname: Singh
authors.forename: K
authors.initials: K
authors.lastname: Bajpai
authors.forename: P
authors.initials: P
authors.lastname: Narayan
authors.forename: V S
authors.initials: VS
authors.lastname: Yadav
authors.forename: V C
authors.initials: VC
authors.lastname: Dhawan
authors.forename: W
authors.initials: W
authors.lastname: Haq
authors.forename: K B
authors.initials: KB
authors.lastname: Mathur
authors.forename: S S
authors.initials: SS
authors.lastname: Agarwal
mesh_terms: D000276:Adjuvants, Immunologic; D002455:Cell Division / Q000187:drug effects; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors*; D013601:T-Lymphocytes / Q000187:drug effects
chemical_list: D000276:Adjuvants, Immunologic; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; C051844:norbinaltorphimine; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D009271:Naltrexone; C024524:beta-funaltrexamine; C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine