Mechanisms involved in the antiplatelet
activity of ketamine in human platelets
蕭哲志;周敦穗
Chang Y;Chen TL;Wu GJ;Hsiao G;Shen MY;Lin KH;Chou DS;Lin
CH;Sheu JR
摘要
Abstract
The aim of this study was to systematically examine the inhibitory mechanisms of ketamine in platelet aggregation. In this study, ketamine concentration-dependently (100-350 microM) inhibited platelet aggregation both in washed human platelet suspensions and platelet-rich plasma stimulated by agonists. Ketamine inhibited phosphoinositide breakdown and intracellular Ca2+ mobilization in human platelets stimulated by collagen. Ketamine (200 and 350 microM) significantly inhibited
thromboxane (Tx) A2 formation stimulated by collagen. Moreover, ketamine (200 and 350 microM) increased the fluorescence of platelet membranes tagged with diphenylhexatriene. Rapid phosphorylation of a platelet protein of Mr 47,000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12,13-dibutyrate (100 nM). This phosphorylation was markedly inhibited by ketamine (350 microM). These results indicate that the
antiplatelet activity of ketamine may be involved in the following pathways. Ketamine may change platelet membrane fluidity, with a resultant influence on activation of
phospholipase C, and subsequent inhibition of phosphoinositide breakdown and
phosphorylation of P47, thereby leading to inhibition of intracellular Ca2+ mobilization and TxA2 formation, ultimately resulting in inhibition of platelet aggregation. 2004 National Science Council, ROC and S. Karger AG, Basel
