title: Effect of the opioid methionine enkephalinamide on signal transduction in human T-lymphocytes.
abstract: T cell receptor (TCR/CD3) induced fluctuations in intracellular free ionizied calcium, [Ca2+]i, was analysed in the human T leukemia cell clone, Jurkat, cultured in the presence of the opioid methionine enkephalinamide (Met-Enk) in titrated concentrations (10[-7] to 10[-15] M) or saline (PBS). In the majority of individual experiments, the activation-induced fluctuations in [Ca2+]i were similar in cells cultured in the presence of Met-Enk and PBS, respectively. However, when all the experimental data from 101 separate TCR/CD3-activation experiments with Met-Enk were compared with the 67 separate control experiments, we found that a fraction (20-40%) of the individual sets of Met-Enk experiments responded significantly different when compared to PBS-controls. In this fraction of experiments the increase in [Ca2+]i after ligation of the TCR/CD3 complex was extremely slow compared to controls. Moreover, the levels of [Ca2+]i in this particular fraction were lower than control levels prior to ligation of the TCR/CD3 complex. The data support the idea that signal transduction in T cells can be influenced by endogenous opioid. The data therefore give credit to the evolving hypothesis of a functional relationship between the neuroendocrine system and the immune system.
authors.affiliation: Department of Medical Anatomy, The Panum Institute, University of Copenhagen, Denmark. A.Norbak@mai.ku.dk
authors.forename: A N
authors.initials: AN
authors.lastname: Sørensen
authors.forename: M H
authors.initials: MH
authors.lastname: Claësson
mesh_terms: D002118:Calcium / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D019169:Jurkat Cells; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry*; D017465:Receptors, Opioid, delta / Q000819:agonists*; D015398:Signal Transduction / Q000187:drug effects*; D013223:Statistics as Topic; D013601:T-Lymphocytes / Q000187:drug effects*
chemical_list: D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell; D017465:Receptors, Opioid, delta; D004744:Enkephalin, Methionine; C021055:Met-enkephalinamide; D002118:Calcium