• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.171.2-172
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• 2000

• 대한약리학회지
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• 제32권1호
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• pp.103-112
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• 1996

Platelet-activating factor (PAF)에 의하여 자극된 호중구 respiratory burst, 탈과립과 세포질 칼슘농도의 증가에 있어 protein kinase C와 protein tyrosine kinase의 역할을 관찰하였다. PAF에 의하여 자극된 호중구에서 superoxide 및 $H_2O_2$의 생성과 myeloperoxidase와 acid phosphatase의 유리는 protein kinase C 억제제인 staurosporine과 H-7 그리고 protein tyrosine kinase 억제제인 genistein과 tyrphostin에 의하여 억제되었다. PAF에 의한 호중구 세포내 칼슘농도의 증가는 staurosporine, genistein과 methyl-2,5-dihydroxycinnamate에 의하여 억제 되었다. Staurosporine은 PAF에 의하여 자극된 호중구에서 세포내 칼슘유리와 망간유입을 억제 하였다. Genistein과 methyl-2,5-dihydroxycinnamate는 PAF에 의한 망간유입을 억제하였으나, 세포내 칼슘유리에 대한 이들의 효과는 관찰되지 않았다. PMA에 의하여 활성화된 호중구에서 세포내 칼슘농도의 증가에 대한 PAF의 자극효과는 감소되었다. Protein kinase C와 protein tyrosine kinase는 PAF에 의하여 자극된 호중구에서의 respiratory burst, lysosomal enzyme유리와 칼슘동원에 관여할 것으로 제시된다. 세포내 칼슘농도의 증가는 protein kinase의 영향을 다르게 받는 세포내 칼슘유리와 세포외부로 부터의 칼슘유입에 의하여 이루어질 것으로 추정된다. Protein kinase C가 활성화되어 있는 상태에서 세포내 칼슘동원에 대한 PAF의 자극작용은 감소될 것으로 시사된다.

• 약학회지
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• 제43권6호
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• pp.809-817
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• 1999

The effect of 2-(4-cyanophenyl)amino-1,4-naphthalenedione-3-pyridinium perchlorate (PQ5) on pla-telet aggregation and its action mechanisms were investigated with rat platelet. PQ5 inhibited the platelet aggregation induced by collagen ($6{\;}{\mu\textrm{g}}/ml$), thrombin (0.4 U/ml) and A23187 ($3{\mu}M$) in concentration-dependent manner with $IC_{50}$ values of 5.50, 25.89 and $37.12{\;}{\mu}M$, respectively. PQ5 also significantly reduced the thromboxane $A_2$ (TXA2) formation in a concentration dependent manner. The collagen-induced arachidonic acid (AA) release in [-3H]-AA incorporated platelet, an indication of the phospholipase $A_2$ activity, was decreased by PQ5 pretreatment PQ5 significantly inhibited the activity of thormboxane synthase only at high concentration ($100{\mu}M$), but did not affect the cyclooxygenase activity at all. Collagen-induced ATP release was significantly reduced by PQ5. Calcium-induced platelet aggregation experiment suggests that the elevation of intracellular free $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) by collagen stimulation is decreased by the pretreatment of PQ5, which is due to the inhibition of calcium release from intracellular store and influx from outside of the cell. PQ5 did not showed the effect of anticoagulation as prothrombin time (PT) or activated partial thromboplastin time (APTT). Form these results, it is suggested that PQ5 exerts its antiplatelet activity through the inhibition of the intracellular $Ca^{2+}$ mobilization and the decrease of the $TXA_2$ synthesis.

• The Korean Journal of Physiology and Pharmacology
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• 제14권2호
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• pp.105-111
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• 2010

Inositol 1,4,5-trisphosphate receptors ($InsP_3Rs$) modulate $Ca^{2+}$ release from intracellular $Ca^{2+}$ store and are extensively expressed in the membrane of endoplasmic/sarcoplasmic reticulum and Golgi. Although caffeine and 2-aminoethoxydiphenyl borate (2-APB) have been widely used to block $InsP_3Rs$, the use of these is limited due to their multiple actions. In the present study, we examined and compared the ability of caffeine and 2-APB as a blocker of $Ca^{2+}$ release from intracellular $Ca^{2+}$ stores and $Ca^{2+}$ entry through store-operated $Ca^{2+}$ (SOC) channel in the mouse pancreatic acinar cell. Caffeine did not block the $Ca^{2+}$ entry, but significantly inhibited carbamylcholine (CCh)-induced $Ca^{2+}$ release. In contrast, 2-APB did not block CCh-induced $Ca^{2+}$ release, but remarkably blocked SOC-mediated $Ca^{2+}$ entry at lower concentrations. In permeabilized acinar cell, caffeine had an inhibitory effect on InsP3-induced $Ca^{2+}$ release, but 2-APB at lower concentration, which effectively blocked $Ca^{2+}$ entry, had no inhibitory action. At higher concentrations, 2-APB has multiple paradoxical effects including inhibition of Ins$P_3$-induced $Ca^{2+}$ release and direct stimulation of $Ca^{2+}$ release. Based on the results, we concluded that caffeine is useful as an inhibitor of $InsP_3R$, and 2-APB at lower concentration is considered a blocker of $Ca^{2+}$ entry through SOC channels in the pancreatic acinar cell.

• The Korean Journal of Physiology and Pharmacology
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• 제10권1호
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• pp.25-30
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• 2006

Lysophosphatidylcholine (LPC), which accumulates in atherosclerotic arteries, has been reported to inhibit endothelium-dependent relaxation (EDR) in many different species. However, the underlying mechanism of LPC-induced inhibition of EDR is still uncertain. In the present study, we measured simultaneously both isometric tension and cytosolic free $Ca^{2+}$ ($[Ca^{2+}]_i$) in rabbit carotid strips, and examined the effect of LPC on tension and $[Ca^{2+}]_i$. In carotid strips with intact-endothelium, high $K^+$ (70 mM) increased both tension and $[Ca^{2+}]_i$, and cumulative addition of acetylcholine (ACh) from 0.1 to $10{\mu}M$ induced dose dependent increase of $[Ca^{2+}]_i$ with concomitant relaxation. In the presence of L-NAME (0.1 mM), ACh increased $[Ca^{2+}]_i$ without affecting the amplitude of high $K^+-induced$ tension. These ACh-induced change of $[Ca^{2+}]_i$ and tension was abolished by removal of endothelium or 10 nM 4-DAMP (muscarinic receptor antagonist) pretreatment. Pretreatment of LPC ($10{\mu}M$) inhibited ACh ($10{\mu}M$)-induced change of tension and $[Ca^{2+}]_i$ in endothelium-intact carotid artery. On the other hand, LPC had no effect on ACh-induced change of tension and $[Ca^{2+}]_i$ in endothelium denuded artery. In $Ca^{2+}$-free external solution, ACh transiently increased $[Ca^{2+}]_i$, and pretreatment of LPC significantly inhibited ACh-induced transient $[Ca^{2+}]_i$ change. Based on the above results, it may be concluded that LPC inhibits the ACh-induced $[Ca^{2+}]_i$ change through inhibition of $Ca^{2+}$ mobilization in vascular endothelial cells, resulting in decreased production of NO and concomitant inhibition of endotheliumdependent vascular relaxation.

• 대한약리학회지
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• 제31권3호
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• pp.333-344
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• 1995

fMLP에 의하여 자극된 중성호성 백혈구에서의 superoxide 생성, myeloperoxidase 유리, 칼슘 동원과 백혈구 부착에 나타내는 adenosine과 $N^6-cyclopentyladenosine$의 효과를 관찰하였다. 또한 이들의 효과를 C5a와 PMA의 자극효과에 대하여 그리고 lipopolysaccharide-primed 중성호성 백혈구의 반응에 대하여 관찰하였다. 이와 함께 adenosine의 억제작용에 있어 cAMP의 관여 여부를 조사하였다. 연구 결과로 부터 fMLP에 의해 자극된 중성호성 백혈구에서의 superoxide 생성, 탈과립과 세포내 칼슘 동원과 백혈구 부착은 adenosine 수용체에 의하여 조절된다고 추정된다. Adenosine은 protein kinase C의 활성화에 따른 백혈구 반응의 자극에 영향을 나타내지 않을 것으로 시사된다. Nonprimed 세포에 비하여, lipopolysaccharide-primed 중성호성 백혈구에서 fMLP에 의한 superoxide 생성은 adenosine의 영향을 적게 받을 것으로 여겨진다. Adenosine 존재하에서 백혈구 반응에 나타내는 theophylline의 억제효과는 세포내 cAMP 축적에 기인할 것으로 추정된다.

• Natural Product Sciences
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• 제26권4호
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• pp.295-302
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• 2020

Cudrania tricuspidata (C. tricuspidata) is a deciduous tree found in Japan, China and Korea. The root, stems, bark and fruit of C. tricuspidata has been used as traditional herbal remedies such as eczema, mumps, acute arthritis and tuberculosis. In this study, we investigated the potential efficacies of this natural compound by focusing on the inhibitory effect of cudraxanthone L (CXL) isolated from the roots of C. tricuspidata on human platelet aggregation. Our study focused on the action of CXL on collagen-stimulated human platelet aggregation, inhibition of platelet signaling molecules such as fibrinogen binding, intracellular calcium mobilization, fibronectin adhesion, dense granule secretion, and thromboxane A2 secretion. In addition, we investigated the inhibitory effect of CXL on thrombin-induced clot retraction. Our results showed that CXL inhibited collagen-induced human platelet aggregation, intracellular calcium mobilization, fibrinogen binding, fibronectin adhesion and clot retraction without cytotoxicity. Therefore, we confirmed that CXL has inhibitory effects on human platelet activities and has potential value as a natural substance for preventing thrombosis.

• BMB Reports
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• 제40권5호
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• pp.678-683
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• 2007

Extracts from the leaves of the Ginkgo biloba are becoming increasingly popular as a treatment that is claimed to reduce atherosclerosis, coronary artery disease, and thrombosis. In this study, the effect of ginkgolide B (GB) from Ginkgo biloba leaves in collagen (10 ${\mu}g/ml$)-stimulated platelet aggregation was investigated. It has been known that human platelets release matrix metallo-proteinase-9 (MMP-9), and that it significantly inhibited platelet aggregation stimulated by collagen. Zymographic analysis confirmed that pro-MMP-9 (92-kDa) was activated by GB to form an MMP-9 (86-kDa) on gelatinolytic activities. And then, activated MMP-9 by GB dose-dependently inhibited platelet aggregation, intracellular $Ca^{2+}$ mobilization, and thromboxane $A_2$ ($TXA_2$) formation in collagen-stimulated platelets. Activated MMP-9 by GB directly affects down-regulations of cyclooxygenase-1 (COX-1) or $TXA_2$ synthase in a cell free system. In addition, activated MMP-9 significantly increased the formation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which have the anti-platelet function in resting and collagen-stimulated platelets. Therefore, we suggest that activated MMP-9 by GB may increase the intracellular cAMP and cGMP production, inhibit the intracellular $Ca^{2+}$ mobilization and $TXA_2$ production, thereby leading to inhibition of platelet aggregation. These results strongly indicate that activated MMP-9 is a potent inhibitor of collagen-stimulated platelet aggregation. It may act a crucial role as a negative regulator during platelet activation.

• 약학회지
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• 제50권6호
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• pp.409-414
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• 2006

Although mammalian sperms are cryopreserved for in vitro fertilization a process of cryopreservation decreases the fertility. Acrosome reaction requires depolarization-induced Ca$^{2+}$ influx and Ca$^{2+}$ releases from the Ca$^{2+}$ stores. To examine whether the cellular Ca$^{2+}$ mobilization is altered by a sperm cryopreservation we compared cytosolic Ca$^{2+}$ signals between fresh and cryopreserved pig sperms using confocal Ca$^{2+}$ imaging. The magnitudes of depolarization induced Ca$^{2+}$ increases were significantly smaller in cryopreserved sperms. Exposures to 10 mM caffeine or 5 ${\mu}$M thapsigargin elicited less Ca$^{2+}$ increases in the cryopreserved sperms compared to fresh sperms. In addition, progesterone-trig-gered Ca$^{2+}$ rises, that are thought to enhance acrosome reaction, were completely abolished in the cryopreserved sperms. These results suggest that storage and(/or) release of Ca$^{2+}$ from the intracellular Ca$^{2+}$ stores in pig sperms are significantly impaired by the process of cryopreservation.

• BMB Reports
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• 제48권1호
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• pp.36-41
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• 2015

Recently, we demonstrated that human serum amyloid P component (SAP) specifically recognizes exposed bacterial peptidoglycan (PGN) of wall teichoic acid (WTA)-deficient Staphylococcus aureus ${\Delta}$tagO mutant cells and then induces complement-independent phagocytosis. In our preliminary experiments, we found the existence of human serum immunoglobulins that recognize S. aureus PGN (anti-PGNIgGs), which may be involved in complement-dependent opsonophagocytosis against infected S. aureus cells. We assumed that purified serum anti-PGN-IgGs and S. aureus ${\Delta}$tagO mutant cells are good tools to study the molecular mechanism of anti-PGN-IgG-mediated phagocytosis. Therefore, we tried to identify the intracellular molecule(s) that is involved in the anti-PGN-IgG-mediated phagocytosis using purified human serum anti-PGN-IgGs and different S. aureus mutant cells. Here, we show that anti-PGN-IgG-mediated phagocytosis in phorbol myristate acetate-treated U937 cells is mediated by $Ca^{2+}$ release from intracellular $Ca^{2+}$ stores and anti-PGN-IgGdependent $Ca^{2+}$ mobilization is controlled via a phospholipase C${\gamma}$-2-mediated pathway.