[Inhibitory effect of kaempferol against binding of platelet activating factor to its receptor].
OBJECTIVE
To observe the platelet activating factor (PAF) antagonistic effect of kaempferol.


METHODS
The specific binding of [3H] PAF to rabbit platelet receptor was investigatedwith 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 determined with Fura-2 fluorescent technique.


RESULTS
The 1, 2 or 4 nmol x L(-1) [3H]PAF specific binding to rabbit platelet receptor was inhibited by Kae dosage dependently and the IC50 were 30.8, 74.6 and 92.0 micro mol x L(-1), respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration elevation were inhibited by Kae in a dose-dependent manner. The IC50 of Kae to inhibit platelet adhesion was 65 micromol x L(-1).


CONCLUSIONS
Kae is effective in inhibiting the action of PAF and it is a new PAF receptor antagonist.
Zang
Bao-Xia
BX
Department of Pharmacology, Beijing Institute of Heart, Lung and Blood Vessel Diseases-Anzhen Hospital, Beijing 100029, China. jinzang@public3.bta.net.cn
Jin
Ming
M
Wu
Wei
W
Chen
Wen-Mei
WM
Piao
Yong-Zhe
YZ
Li
Jin-Rong
JR
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D044949:Kaempferols / Q000494:pharmacology*; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D010972:Platelet Activating Factor / Q000378:metabolism*; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011817:Rabbits; D011869:Radioligand Assay; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000378:metabolism
D044949:Kaempferols; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; C039351:platelet activating factor receptor; C006552:kaempferol; D002118:Calcium