• Biomolecules & Therapeutics
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• 제7권3호
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• pp.227-233
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• 1999

The effects of 2-bromo-3-(3,5-tert-butyl-4-hydroxylphenyl)-1,4-naphthalenedione(TPN2), a synthetic vitamin K derivative, on platelet aggregation and its action mechanisms were investigated in rat platelet. TPN2 inhibited the platelet aggregation induced by collagen($10\mu\textrm{g}$/ml), thrombin(0.1 U/ml), A23187($10\mu\textrm{M}$) and arachidonic acid($100\mu\textrm{M}$) in concentration-dependent manner with $IC_{50}$ values of 6.5$\pm$1.3, 59.3$\pm$4.5, 13.0$\pm$2.37 and 2.9$\pm$$1.0\mu\textrm{M}$, respectively. Collagen-induced serotonin release was significantly reduced by TPN2. The elevation of intracellular free $Ca^{2+}$ concentration ([$Ca^{2+}$]i) by collagen stimulation was greatly decreased by the pretreatment of TPN2, which was due to the inhibition of calcium release from intracellular store and influx from outside of the cell. TPN2 also significantly reduced the thromboxane $A_2$($TXA_2$) formation in a concentration-dependent manner. The collagen-induced arachidonic acid (AA) release in [$^3H$]-AA incorporated platelet, an indicative of the phospholipase $A_2$ activity, was decreased by TPN2 pretreatment. TPN2 significantly inhibited the activity of thromboxane synthase, but did not affect the cyclooxygenase activity. From these results. it is suggested that TPN2 exert its antiplatelet activity through the inhibition of the intra-cellular $Ca^{2+}$ mobilization and the decrease of the $TXA_2$ synthesis.

• 한국동물학회지
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• 제38권4호
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• pp.457-464
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• 1995

인간의 상피세포로부터 유래된 암세포의 일종인 HeLa 세포는 거의 모든 기질분자에 부착하지만 spreading은 오직 collagen 혹은 gelatin에서만 일어난다. HeLa 세포의 spreading은 오직 collagen 결과 활성화된 phosphoipase $A_2$(PLA$_2$)에 의한 arachidonic acid(AA)의 형성으로 유도된다. PLA$_2$에 의해 분해되는 인지질을 확인하기 위해 각종 인지질의 농도변화를 spreading 과정에서 측정한 결과 단지 phosphatidylcoline 만이 감소하였으며, 또한 다양한 lysophospholipids 중 lysophosphatidylcholine 만이 spreading 과정에 생성되는 것으로 보아 phosphatidylcoline이 PLA$_2$에 의해 분해되어 AA가 형성되는 것으로 보인다. PLA$_2$의 활성화는 세포질 CA$_2$+의 농도변화 및 세포질 pH의 알칼리화에 기인하지 않으며, 또한 pertussis 혹은 cholera toxin-sensitive G protein 역시 PLA$_2$활성화와는 무관한 것으로 나타났다.