Effects of tetrandrine, Fura 2-AM, and Bay k 8644 on platelet-activating factor release from rat peritoneal macrophages stimulated by lipopolysaccharides
Abstract
AIM: To study the relationship between the calcium and the release of platelet-activating factor (PAF) from rat peritoneal macrophages (PMø) stimulated by lipopolysaccharides (LPS).
METHODS: The effects of tetrandrine (Tet), Fura 2-AM, and Bay k 8644 on the PAF release from rat PMø was investigated by the bio-assay of PAF.
RESULTS: LPS stimulated PMø to release PAF, without increasing intracellular Ca2+ of PMø, Tet at 0.1, 1.0, 10, 100 mumol.L-1 and Fura 2-AM at 0.01, 0.1, 1.0, 10 mumol.L-1 could dose-dependently decrease the release of PAF (9.8 +/- 1.2, 6.5 +/- 1.6, 4.7 +/- 0.8, 3.4 +/- 0.4 microgram.L-1 and 9.2 +/- 1.7, 5.2 +/- 1.3, 3.7 +/- 0.4, 3.2 +/- 0.3 microgram.L-1, respectively, no drugs 11.8 +/- 1.2 micrograms.L-1), Bay k 8644 at 1.0, 5.0, 10 mumol.L-1 could dose-dependently increase the release of PAF (13.2 +/- 1.7, 16.2 +/- 1.4, 17.6 +/- 1.5 micrograms.L-1), and the effects of Tet and Fura 2-AM were completely or partly reversed by Bay k 8644 at 5.0 mumol.L-1.
CONCLUSION: Although LPS did not increase intracellular Ca2+ of PMø, intracellular Ca2+ was necessary for PAF release from rat PMø stimulated by LPS.
Keywords:
METHODS: The effects of tetrandrine (Tet), Fura 2-AM, and Bay k 8644 on the PAF release from rat PMø was investigated by the bio-assay of PAF.
RESULTS: LPS stimulated PMø to release PAF, without increasing intracellular Ca2+ of PMø, Tet at 0.1, 1.0, 10, 100 mumol.L-1 and Fura 2-AM at 0.01, 0.1, 1.0, 10 mumol.L-1 could dose-dependently decrease the release of PAF (9.8 +/- 1.2, 6.5 +/- 1.6, 4.7 +/- 0.8, 3.4 +/- 0.4 microgram.L-1 and 9.2 +/- 1.7, 5.2 +/- 1.3, 3.7 +/- 0.4, 3.2 +/- 0.3 microgram.L-1, respectively, no drugs 11.8 +/- 1.2 micrograms.L-1), Bay k 8644 at 1.0, 5.0, 10 mumol.L-1 could dose-dependently increase the release of PAF (13.2 +/- 1.7, 16.2 +/- 1.4, 17.6 +/- 1.5 micrograms.L-1), and the effects of Tet and Fura 2-AM were completely or partly reversed by Bay k 8644 at 5.0 mumol.L-1.
CONCLUSION: Although LPS did not increase intracellular Ca2+ of PMø, intracellular Ca2+ was necessary for PAF release from rat PMø stimulated by LPS.