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XANTHINES INHIBIT HUMAN PLATELET AGGREGATION INDUCED BY PLATELET‐ACTIVATING FACTOR
Author(s) -
Misso N. L. A.,
Thompson P. J.
Publication year - 1992
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1992.tb00510.x
Subject(s) - theophylline , platelet activating factor , chemistry , platelet , ic50 , adenosine diphosphate , pharmacology , adenosine , platelet aggregation , adenosine triphosphate , inhibitory postsynaptic potential , biochemistry , in vitro , medicine
SUMMARY 1. Platelet‐activating factor (PAF) may be involved in the pathogenesis of asthma, and therefore the effects of the anti‐asthma drugs theophylline and enprofylline on human platelet aggregation and adenosine triphosphate (ATP) release induced by PAF and adenosine diphosphate (ADP) were studied. 2. Enprofylline (50% inhibitory concentration [IC 50 ] = 94.8±13.2 μmol/L) was more potent than theophylline (IC 50 = 934.1±40.1 μmol/L) as an inhibitor of PAF‐induced aggregation, and the xanthines were twice as potent as inhibitors of PAF‐induced aggregation when compared with ADP‐induced aggregation. ATP release was 1.4 times more sensitive to inhibition by the xanthines than aggregation. 3. Although high concentrations of xanthines inhibited platelet aggregation and ATP release induced by PAF, therapeutic concentrations are unlikely to inhibit PAF‐induced effects.