Muramyl dipeptide mimicry in the regulation of murine macrophage activation by serotonin.
Muramyl peptides (MPs) are regulators of macrophage function. That the activities of MPs may be mediated by serotonin (5-HT) is supported by earlier work that demonstrated specific binding sites for MPs on macrophages that competitively bind 5-HT. Both mediators were also shown to enhance the production of superoxide anion (an antibacterial agent) by these cells. We now report on two additional macrophage activation phenomena affected by 5-HT: phagocytosis and induction of tumor necrosis factor alpha (TNF) mRNA. Serotonin acts as a muramyl peptide-like agonist by increasing phagocytosis of tubercle bacilli by murine peritoneal macrophages, and as a partial agonist/antagonist in the induction of mRNA for tumor necrosis factor. These observations provide further evidence for a serotonergic involvement in some of the physiological responses to MPs.
Polanski
M
M
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Vermeulen
M W
MW
Wu
J
J
Karnovsky
M L
ML
D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000276:immunology / Q000494:pharmacology*; D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D007375:Interleukin-1 / Q000235:genetics; D007457:Iodine Radioisotopes; D008262:Macrophage Activation / Q000187:drug effects*; D008297:Male; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000276:immunology; D010587:Phagocytosis / Q000187:drug effects; D012701:Serotonin / Q000276:immunology / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000235:genetics
D000276:Adjuvants, Immunologic; D007375:Interleukin-1; D007457:Iodine Radioisotopes; D014409:Tumor Necrosis Factor-alpha; D012701:Serotonin; D000119:Acetylmuramyl-Alanyl-Isoglutamine