title: The nitric oxide-producing properties of Ulmi radicis cortex extract.
abstract: We investigated the effect of Ulmi radicis cortex extract (UrCE) on the production of nitric oxide (NO). Stimulation of mouse peritoneal macrophages with UrCE after the treatment of recombinant interferon-gamma (rIFN-gamma) resulted in the increased NO synthesis. UrCE had no effect on NO synthesis by itself. When UrCE was used in combination with rIFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. The optimal effect of UrCE on NO synthesis was shown 6 h after treatment with rIFN-gamma. NO production was inhibited by NG-monomethyl-L-arginine. The increased production of NO from rIFN-gamma plus UrCE-stimulated cells was decreased by the treatment of protein kinase C inhibitor such as staurosporin. In addition, synergy between rIFN-gamma and UrCE was mainly dependent on UrCE-induced tumor necrosis factor-alpha (TNF-alpha) secretion. All the preparations of UrCE were endotoxin free. These results suggest that the capacity or UrCE to increase NO production from rIFN-gamma-primed mouse peritoneal macrophages is the result of UrCE-induced TNF-alpha secretion.
mesh_terms: D000818:Animals; D007371:Interferon-gamma / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis*; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal; D011817:Rabbits; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology