Effects of tetrandrine, Fura 2-AM, and Bay k 8644 on platelet-activating factor release from rat peritoneal macrophages stimulated by lipopolysaccharides.
OBJECTIVE
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.


CONCLUSIONS
Although LPS did not increase intracellular Ca2+ of PMø, intracellular Ca2+ was necessary for PAF release from rat PMø stimulated by LPS.
Song
S Q
SQ
Department of Pharmacology, Third Military Medical University, Chongqing, China.
Hu
Y M
YM
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines; D001681:Biological Assay; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D016257:Fura-2 / Q000031:analogs & derivatives* / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000378:metabolism*; D010972:Platelet Activating Factor / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar
D000470:Alkaloids; D044182:Benzylisoquinolines; D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; D010972:Platelet Activating Factor; D011135:Polysaccharides, Bacterial; C049925:fura-2-am; C009438:tetrandrine; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D016257:Fura-2