title: Enhancement of interleukin-1 production in mouse peritoneal macrophages by methionine-enkephalin.
abstract: Methionine-enkephalin, an endogenous opioid, has been reported to have some effects on immune responses. By thymocyte proliferation method, we herein report that methionine-enkephalin over a wide range of concentrations (1 pmol-0.1 mumol/L) significantly increases both extracellular interleukin-1 release and intracellular interleukin-1 production from peritoneal macrophages induced by lipopolysaccharide in mice. Naloxone, having no effect per se on interleukin-1 production, does not block the enhancing effect of the neuropeptide. Interleukin-1 production was also elevated following ip methionine-enkephalin into mice. The results suggest that methionine-enkephalin mediates the enhancement of interleukin-1 synthesis and release as well, and that the effect is not mediated through classical opioid receptors. The results also provide the further links between immune and nervous systems.
authors.forename: S X
authors.initials: SX
authors.lastname: Yang
authors.forename: X Y
authors.initials: XY
authors.lastname: Li
mesh_terms: D000818:Animals; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D005260:Female; D007375:Interleukin-1 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010529:Peritoneal Cavity / Q000166:cytology
chemical_list: D007375:Interleukin-1; D008070:Lipopolysaccharides; D004744:Enkephalin, Methionine