[Antagonistic effect of myricetin on platelet activing factor].
OBJECTIVE
To study the antagonistic effect of myricetin on platelet activing factor (PAF).


METHODS
The specific binding of [3H] PAF to rabbit platelet receptor was investigated using radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was assayed by Fura-2 fluorescent technique.


RESULTS
The specific binding inhibition potency of Myr was found to be concentration-dependent. The IC50 of Myr in [3H] PAF 1, 2 and 4 nmol.L-1 were 34.8, 85.7 and 118.6 mumol.L-1, respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration increase were inhibited by Myr in a dose-dependent manner. The IC50 of Myr to inhibit platelet adhesion was 13.1 mumol.L-1.


CONCLUSIONS
The specific receptor binding of PAF can be antagonized by myricetin.
Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Beijing 100029, China.
Bao-xia
BX
Zang
Ming
M
Jin
Wei
W
Wu
Wen-mei
WM
Chen
Yong-zhe
YZ
Piao
Jin-rong
JR
Li
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology*; D008297:Male; D009504:Neutrophils / Q000378:metabolism*; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D011817:Rabbits; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism
D005419:Flavonoids; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; C039351:platelet activating factor receptor; C040015:myricetin; D002118:Calcium