title: Inhibition of interleukin-2 production and downregulation of IL-2 and transferrin receptors on rat splenic lymphocytes following PAG morphine administration: a role in natural killer and T cell suppression.
abstract: We investigated the effects of acute injection of morphine into the rat mesencephalon periaqueductal gray (PAG), on splenic natural killer (NK) cell and lymphocyte functions, interleukin-2 (IL-2) production, expression of T cell (CD3), T helper cell (CD4), T suppressor cell (CD8), and NK cell (NKR-P1) surface markers, and expression of IL-2 (CD25) and transferrin (CD71) receptors. Bilateral microinjection of 10 nmol of morphine in the PAG significantly (p < 0.001) inhibited IL-2 (31%) production by activated splenic lymphocytes compared with that of PAG saline-injected control rats. In addition, morphine significantly (p < 0.01) suppressed splenic NK cell activity (14-33%) and T lymphocyte proliferative responses (25-48%) to various mitogens compared with controls. Furthermore, morphine did not alter the expression of CD3, CD4, CD8, and NKR-P1 surface markers, but significantly (p < 0.001) downregulated the expression of CD25 and CD71 receptors following in vitro activation. These results suggested that injection of morphine in the PAG suppresses NK and T cell functions by reducing the ability of T cells to produce IL-2 and downregulating the expression of CD25 and CD71 surface activation markers.
authors.affiliation: Department of Biomedical and Therapeutic Sciences, University of Illinois, College of Medicine, Peoria 61656, USA.
authors.forename: R
authors.initials: R
authors.lastname: Gomez-Flores
authors.forename: R J
authors.initials: RJ
authors.lastname: Weber
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D002478:Cells, Cultured; D015536:Down-Regulation; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000378:metabolism; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D010487:Periaqueductal Gray / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D015375:Receptors, Interleukin-2 / Q000276:immunology; D011990:Receptors, Transferrin / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C068126:CD71 antigen; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011990:Receptors, Transferrin; D009020:Morphine