• Archives of Pharmacal Research
• /
• v.21 no.6
• /
• pp.774-778
• /
• 1998

Brazilin [7,11b-dihydrobenz[b]indeno[1,2-d]pyran-3,6a,9,10(6H)-tetrol] inhibited thrombin-, collagen- and ADP-induced aggregation of washed rat platelets. T hrombin- and collagen-induced ATP release were also inhibited by brazilin in a concentration-dependent manner. Brazilin inhibited the formation of platelet thromboxane $A_2$ caused by thrombin, whereas it had no effect on the prostaglandin $D_2$ formation. Brazilin inhibited $^3H$-arachidonic acid liberation from membrane phospholipids of thrombin-stimulated platelets. Brazilin inhibited the rise of intracellular free calcium caused by thrombin. These results indicate that the inhibition of phospholipase ($PLA_2$) activity and [$[Ca^{2+}]_1$ elevation might be at least a part of antiplatelet mechanism of brazilin.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.3
• /
• pp.919-923
• /
• 2004

Spirodela polyrhiza(L.) Schleid (Lemnaceae) have been used as a traditional drug in treating urticaria and itching. However, the exact role of Spirodela polyrhiza in allergic reaction has not been clarified yet. Type 1 hypersensitivity (immediate hypersensitivity), popularly known as allergy, is a major clinical problem in humans. It has been found that the histamine release from mast cells is an essential step in the pathological process of immediate hypersensitivity. In the present study, the effect of aqueous extract of Spirodela polyrhiza (AESP) on immediate hypersensitivity was investigated. AESP inhibited the antigen-induced passive cutaneous anaphylaxis (PCA). AESP in vitro exhibited a dose-dependent inhibition of degranulation in RPMC stimulated by compound 48/80. AESP also suppressed the morphological changes and the increase of intracellular free calcium level induced by compound 48/80. These results suggest that inhibitory effect of AESP on immediate hypersensitivity may be mediated through the decrease of intracellular free calcium levels, and AESP importantly contributes to the treatment of anaphylaxis and may be useful for other allergic disease.

• Biomolecules & Therapeutics
• /
• v.11 no.3
• /
• pp.174-177
• /
• 2003

The present experiment was performed to investigate the protective effects of paeonol isolated from Moutan Cortex Radicis on primary cultured rat hepatocytes exposed to Br-A23187 ($Ca^{2+}$ ionophore). Br-A23187 is frequently used as a model of cell killing as inducing both necrotic and apoptotic cell death. Hepatocytes were isolated by collagenase perfusion from livers of fasted male Sprague Dawley rats and cultured overnight. Cell viability was determined by propidium iodide using fluorocytometry in Krebs-Ringer-HEPES buffer at pH 7.4. In addition, intracellular calcium was measured by excitation at 340 and 380 nm and emission at 505 nm using a luminescence spectrophotometer. Paeonol (20-100 ${\mu}M$) inhibited cell killing induced by 10 ${\mu}M$ Br-A23187, in a dose-dependent manner. Paeonol also reduced increased intracellular calcium level when hepatocytes were exposed to Br-A23187. Therefore, the present results suggest that paeonol protects the hepatocytotoxicity induced by Br-A23187, via inhibiting the influx of calcium into into rat hepatocytes.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.17 no.1
• /
• pp.154-162
• /
• 2004

The flowers of Lonicera japonica Thunb. (Caprifoliaceae) have been used as a traditional effective drug in treating bacillary dysentery, purulence. However, the exact role of Lonicera japonica in allergic reaction has not been clarified yet. Immediate hypersensitivity, popularly known as allergy, is a major clinical problem in humans. It has been found that the histamine release from mast cells is an essential step in the pathological process of immediate hypersensitivity. In this study, the effect of aqueous extract of Lonicera japonica (AELJ) on allergic reaction was investigated. AELJ inhibited the compound 48／80-induced anaphylactic reactions and antigen-induced passive cutaneous anaphylaxis (PCA). AELJ in vitro exhibited a dose-dependent inhibition of degranulation in RPMC stimulated by compound 48／80. AELJ also suppressed the morphological changes and the increase of intracellular free calcium level induced by compound 48／80. These results suggest that inhibitory effect of AELJ on allergic reaction may be mediated through the decrease of intracellular free calcium levels, and AELJ importantly contributes to the treatment of anaphylaxis and may be useful for other allergic disease.

• The Korean Journal of Physiology and Pharmacology
• /
• v.11 no.3
• /
• pp.89-95
• /
• 2007

Polygala tenuifolia (PT) is one of the most well-known traditional herbal medicines in Korea which is commonly used for the treatment of cardiovascular symptoms. The anti-ischemic effects of PT in isolated rat heart was investigated by analyzing changes in blood pressure, aortic flow, coronary flow, and cardiac output. And, its underlying mechanism was examined by quantitating intracellular calcium content in rat neonatal cardiomyocytes. Rats were divided into two groups: an ischemia-induced group without any treatment, and an ischemia-induced group treated with PT. Ischemia of isolated heart was induced by stopping the supply of oxygen and buffer for 10 min. The isolated heart was exposed to PT for the first 5 min of 10 min ischemia. PT treatment significantly prevented the decreases of perfusion pressure, aortic flow, coronary flow, and cardiac output under ischemic conditions. In addition, hemodynamics (except heart rate) of the PT-treated group was significantly recovered 60 min after reperfusion compared to the control group (systolic aortic pressure: 83.3% vs. 64.9%, aortic flow volume: 69.5% vs. 48.7%, coronary flow volume: 77.7% vs. 58.4%, and cardiac output: 71.6% vs. 51.2%, p < 0.01). As for the underlying mechanism, PT significantly prevented intracellular calcium increase which was induced by isoproterenol (p < 0.01), suggesting that the anti-ischemic effect of PT is mediated by inhibition of intracellular calcium increase.

• BMB Reports
• /
• v.29 no.3
• /
• pp.200-204
• /
• 1996

Nerve growth factor (NGF) is literally known to promote neural differentiation and survival in several peripheral and central neurons. Thus, it is Widely believed that NGF may serve as a therapeutic agent for many types of neuronal diseases. One of the mechanisms suggested to explain the protective role of NGF is that the trophic factor can prevent the increase of intracellular calcium ions which might be responsible for neural death. To examine whether or not the calcium hypothesis works even under pathological conditions, we applied NGF to cultures deprived of glucose. Surprisingly, what was observed here is that NGF rather promoted cell death under a glucose-deprived condition. What we call the NGF paradox phenomenon occurred in a calcium concentration-dependent manner, indirectly suggesting that NGF might increase intracellular calcium ions in cells deprived of glucose. This suggestion is further supported by the fact that nifedipine, a well-known L-type calcium channel blocker, could block the cell death potentiated by NGF. Here it is still premature to propose the complete mechanism underlying the NGF paradox phenomenon. However, this study certainly indicates that NGF as a therapeutic agent for neuronal diseases should be carefully considered before use.

• Biomolecules & Therapeutics
• /
• v.24 no.4
• /
• pp.371-379
• /
• 2016

Store-operated calcium entry (SOCE), a major mode of extracellular calcium entry, plays roles in a variety of cell activities. Accumulating evidence indicates that the intracellular calcium ion concentration and calcium signaling are critical for the responses induced by oxidative stress. The present study was designed to investigate the potential effect of SOCE inhibition on $H_2O_2$-induced apoptosis in endothelial progenitor cells (EPCs), which are the predominant cells involved in endothelial repair. The results showed that $H_2O_2$-induced EPC apoptosis was reversed by SOCE inhibition induced either using the SOCE antagonist ML-9 or via silencing of stromal interaction molecule 1 (STIM1), a component of SOCE. Furthermore, SOCE inhibition repressed the increases in intracellular reactive oxygen species (ROS) levels and endoplasmic reticulum (ER) stress and ameliorated the mitochondrial dysfunction caused by $H_2O_2$. Our findings provide evidence that SOCE inhibition exerts a protective effect on EPCs in response to oxidative stress induced by $H_2O_2$ and may serve as a potential therapeutic strategy against vascular endothelial injury.

• Biomedical Science Letters
• /
• v.13 no.4
• /
• pp.333-339
• /
• 2007

Recently, much attention has been paid to human retinoblastoma since it provide a good model system for studying mechanisms underlying cell growth, differentiation, proliferation, and apoptosis, and for developing cancer therapy. However, until now it is unclear whether purinergic receptors are involved in the calcium mobilization in the retinoblastoma cells. In this regard, we measured possible purinergic signaling in WERI-Rb-1 cells using $Ca^{2+}$ imaging technique and RT-PCR method. ATP-induced $[Ca^{2+}]_i$ transients was maintained to about $90.7{\pm}1.0%$ of the control (n=48) even in the absence of extracellular calcium. The ATP-induced intracellular calcium response was only attained to $10.4{\pm}1.8%$ (n=55) of peak amplitude of the control after preincubation of 1 ${\mu}MU-73122$, a PLC inhibitor, but it was not affected by 1 ${\mu}MU-73343$, a inactive form of U-73122. And also ATP-induced $[Ca^{2+}]_i$ rise was almost attenuated by 20 ${\mu}M$ 2-APB, a putative $IP_3$ receptor inhibitor. Two subtypes of $IP_3$ receptor $(IP_{3-1}R,\;IP_{3-2}R)$ were identified by a RT-PCR method. These findings suggest that purinergic stimuli can cause calcium mobilization via $PLC-IP_3$ pathway after the activation of P2Y receptors in the retinoblastoma cells, which may play important roles in cell proliferation, differentiation, growth, and cell death.

• The Journal of Natural Sciences
• /
• v.10 no.1
• /
• pp.39-47
• /
• 1998

In the present study, We have tested the potential effects of ginseng saponin fractions on macrophage chemotaxis and intracellular calcium and F-actin mobilization. Peritoneal macrophages treated with various ginseng saponin fractions showed 28.4% to 71% of increasement of chemotaxis as compared with untreated cells. The activity of intracelluar calcium mobilization was increased up to 65% by treatment with saponins, and F-actin content also increased 10% in the cells loaded with NBD-phallacidin. When the cells were activated with calcium of PMA and treated with saponin fractions, the intracelluar F-actin content increased significantly and prolonged for 2 minutes. These results suggest that ginseng saponin fractions might be a chemoattractants.

• Biomolecules & Therapeutics
• /
• v.31 no.1
• /
• pp.59-67
• /
• 2023

Thrombin is a serine protease that participates in a variety of biological signaling through protease-activated receptors. Intestinal myofibroblasts play central roles in maintaining intestinal homeostasis. In this study, we found that thrombin-induced apoptosis is mediated by the calcium-mediated activation of cytosolic phospholipase A₂ in the CCD-18Co cell. Thrombin reduced cell viability by inducing apoptosis and proteinase-activated receptor-1 antagonist attenuated thrombin-induced cell death. Endogenous ceramide did not affect the cell viability itself, but a ceramide-mediated pathway was involved in thrombin-induced cell death. Thrombin increased intracellular calcium levels and cytosolic phospholipase A₂ activity. The ceramide synthase inhibitor Fumonisin B1, intracellular calcium chelator BAPTA-AM, and cytosolic phospholipase A₂ inhibitor AACOCF₃ inhibited thrombin-induced cell death. Thrombin stimulated arachidonic acid release and reactive oxygen species generation, which was blocked by AACOCF₃, BAPTA-AM, and the antioxidant reagent Trolox. Taken together, thrombin triggered apoptosis through calcium-mediated activation of cytosolic phospholipase A₂ in intestinal myofibroblasts.