Effect of BN 52021, a specific antagonist of platelet activating factor (PAF-acether), on calcium movements and phosphatidic acid production induced by PAF-acether in human platelets
/sup 32/P-labelled human platelets loaded with quin 2 and pretreated with aspirin were stimulated with 1-100 nM platelet activating factor (PAF-acether or 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in a medium containing the ADP-scavenging system creatine phosphate/creatine phosphokinase. Under these conditions, PAF-acether evoked a characteristic fluorescence change allowing to quantify elevations in cytoplasmic free Ca/sup 2 +/ from internal stores (Ca/sup 2 +/ mobilization) or from external medium (Ca/sup 2 +/ influx), as well as an increased production of phosphatidic acid, reflecting phospholipase C activation. These effects, which can be attributed to PAF-acether only and not to released products such as ADP or thromboxane A2, were strongly inhibited in a dose-dependent manner by BN 52021, a specific antagonist of PAF-acether isolated from Ginkgo biloba. As the drug remained inactive against the same effects elicited by thrombin, it is concluded that BN 52021 does not interfere directly with the mechanism of transmembrane signalling involving inositol-phospholipids or (and) some putative receptor-operated channels, but rather acts on the binding of PAF-acether to its presumed membrane receptor.
- Research Organization:
- INSERM Unite 101, Hopital Purpan, Toulouse, France
- OSTI ID:
- 6409112
- Journal Information:
- Thromb. Res.; (United States), Vol. 4
- Country of Publication:
- United States
- Language:
- English
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BLOOD COAGULATION FACTORS
BIOCHEMICAL REACTION KINETICS
CALCIUM COMPOUNDS
MEMBRANE TRANSPORT
PHOSPHORIC ACID ESTERS
BIOSYNTHESIS
BLOOD PLATELETS
DOSE-RESPONSE RELATIONSHIPS
LIPASE
PHOSPHORUS 32
PHOSPHOTRANSFERASES
THROMBIN
TRACER TECHNIQUES
ALKALINE EARTH METAL COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBOXYLESTERASES
COAGULANTS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYMES
ESTERASES
ESTERS
HEMATOLOGIC AGENTS
HEMOSTATICS
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MATERIALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PEPTIDE HYDROLASES
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
RADIOISOTOPES
REACTION KINETICS
SERINE PROTEINASES
SYNTHESIS
TRANSFERASES
550201* - Biochemistry- Tracer Techniques