• The Korean Journal of Physiology and Pharmacology
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• 제18권6호
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• pp.525-530
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• 2014

Transient receptor potential vanilloid subtype 1 (TRPV1) was originally found in sensory neurons. Recently, it has been reported that TRPV1 is expressed in salivary gland epithelial cells (SGEC). However, the physiological role of TRPV1 in salivary secretion remains to be elucidated. We found that TRPV1 is expressed in mouse and human submandibular glands (SMG) and HSG cells, originated from human submandibular gland ducts at both mRNA and protein levels. However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ($[Ca^{2+}]_i$) in these cells, although carbachol consistently increased $[Ca^{2+}]_i$. Exposure of cells to high temperature (> $43^{\circ}C$) or acidic bath solution (pH5.4) did not increase $[Ca^{2+}]_i$, either. We further examined the role of TRPV1 in salivary secretion using TRPV1 knock-out mice. There was no significant difference in the pilocarpine (PILO)-induced salivary flow rate between wild-type and TRPV1 knock-out mice. Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone. Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.

• Archives of Pharmacal Research
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• 제28권6호
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• pp.699-708
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• 2005

The present study was designed to investigate the effect of naloxone, a well known opioid antagonist, on the secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane-depolarization in the isolated perfused rat adrenal glands, and to establish its mechanism of action. Naloxone ($10^{-6}\~10^{-5}$ M), perfused into an adrenal vein for 60 min, produced dose- and time-dependent inhibition of CA secretory responses evoked by ACh ($5.32\times10^{-3}$ M), high K+ ($5.6\times10^{-2}$ M), DMPP ($10^{-4}$ M) and McN-A-343 ($10^{-4}$ M). Naloxone itself also failed to affect the basal CA output. In adrenal glands loaded with naloxone ($3\times10^{-6}$ M), the CA secretory responses evoked by Bay-K-8644, an activator of L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$-ATPase, were also inhibited. In the presence of met-enkephalin ($5\times10^{-6}$ M), a well known opioid agonist, the CA secretory responses evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were also significantly inhibited. Taken together, these results suggest that naloxone greatly inhibits the CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as that by membrane depolarization. It seems that these inhibitory effects of naloxone does not involve opioid receptors, but might be mediated by blocking both the calcium influx into the rat adrenal medullary chromaffin cells and the uptake of $Ca^{2+}$ into the cytoplasmic calcium store, which are at least partly relevant to the direct interaction with the nicotinic receptor itself.

• 대한수의학회지
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• 제55권4호
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• pp.233-240
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• 2015

Although the effects of the rice bran have recently been investigated, there is no information regarding platelet physiology available. However, it is well known that fermented natural plants have a beneficial effect on cardiovascular diseases. Therefore, this study was conducted to investigate whether fermented rice bran extract (FRBE) with several plants (Artemisia princeps, Angelica Gigantis Radix, Cnidium officinale, and Camellia sinensis) affected agonist-induced platelet aggregation, and if so, what the underlying mechanism of its activity was. We performed several experiments, including in vitro platelet aggregation, intracellular calcium concentration and adenosine triphosphate release. In addition, the activation of integrin ${\alpha}_{II}b{\beta}3$ was determined using fibrinogen binding. Thrombus formation was also evaluated in vivo using an arterio-venous shunt model. The FRBE inhibited collagen-induced platelet aggregation in a concentration-dependent manner. FRBE significantly and dose dependently attenuated thrombus formation using rat arterio-venous shunt. FRBE suppressed the intracellular calcium mobilization in collagen-stimulated platelets. We also found that FRBE inhibited extracellular stimuli-responsive kinase 1/2, p38-mitogen-activated protein kinases and c-Jun N-terminal kinase phosphorylation. These results suggested that FRBE inhibited collagen-induced platelet aggregation, which was mediated by modulation of downstream signaling molecules. In conclusion, FRBE could be developed as a functional food against aberrant platelet activation-related cardiovascular diseases.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.146-146
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• 1998

The present study was designed to examine the effect of total ginseng saponin on contractile responses of vasoconstrictors in the rat aorta. Phenylephrine (an adrenergic ${\alpha}$$_1$-receptor agonist) and high potassium (a membrane depolarizing agent) caused greatly contractile responses in the rat aorta, respectively. However, in the presence of total ginseng saponin (600 $\mu\textrm{g}$/$m\ell$), the contractile responses of phenylephrine (10$\^$-5/ and 10$\^$-7/ M) and high potassium (3.5 ${\times}$ 10$\^$-2/ and 5.6 ${\times}$ 10$\^$-2/ M) were markedly potentiated whereas prostaglandin F$\sub$2${\alpha}$/ (5 ${\times}$ 10$\^$-6/ M)-induced contractile response was not affected. The contractile responses induced by phenylephrine (10$\^$-5/ M) and high potassium (3.5 ${\times}$ 10$\^$-2/ M) even in the presence of total ginseng saponin (600 $\mu\textrm{g}$/$m\ell$) were greatly inhibited by the pretreatment of nicardipine (10$\^$-6/ M), a calcium channel blocker. Taken together, these experimental results suggest that total ginseng saponin can enhance the contractile responses evoked by stimulation of adrenergic ${\alpha}$$_1$-receptor and the membrane depolarization in the rat aorta, which seems to be associated to calcium influx.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.51-51
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• 2003

The medicinal plant Cimicifuga Racemosa (Black cohosh) has been used to treat many kinds of neuronal and menopausal symptoms, such as arthritis, menopausal depression, nerve pain, etc. Here, we examined the effect of Cimicifugoside (CF), one of triterpene glycosides which have been known as pharmacologically active ingredients of C. Racemosa, on nicotinic acetylcholine receptor (nAChR)-mediated catecholamine (CA) secretion in bovine adrenal chromaffin cell. Cimicifugoside inhibited calcium increase induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), a nAChR agonist with a half maximal inhibitory concentration (IC50) of 18${\pm}$2${\mu}$M. In contrast, cimicifugoside did not affect the calcium increases evoked by high K$\^$+/, veratridine, and bradykinin. The DMPP-induced sodium increase was also inhibited by cimicifugoside with IC50 of 2${\pm}$0.3${\mu}$M, suggesting that the activity of nAChRs is inhibited by cimicifugoside. Cimicifugoside did not effect on the KCl-induced secretion but markedly inhibited the DMPP-induced catecholamine secretion which was monitored by carbon-fiber amperometry in real time, and by high performance liquid chromatography (HPLC) through electrochemical detection. The results suggest that cimicifugoside selectively inhibits nAChR-mediated response in bovine chromaffin cells.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.401-415
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• 2002

Lim and his coworkers (1987; 1988; 1989) have also found that all of total Ginseng saponin, panaxadiol-and panaxatriol-type saponins cause the increased secretion of catecholamines (CA) in a $Ca^{2+}$ -dependent fashion from the isolated perfused rabbit adrenal glands through the activation of cholinergic (both nicotinic and muscarinic) receptors. These CA secretory effects are partly due to the direct action on the rabbit adrenomedullary chromaffin cells. However, the present study was designed to examine the effect of total ginseng saponin on CA secretion evoked by activation of cholinergic nicotinic receptors in the isolated perfused model of the rat adrenal gland. Total ginseng saponin given (100 ${\mu}g$/20 min) into an adrenal vein did fail to produce alteration of spontaneous CA release from the rat adrenal medulla. Acetylcholine(5.32 mM)- and DMPP(100 ${\mu}M$, a selective nicotinic receptor agonist)-evoked CA secretory responses were reduced markedly after the pretreatment with the total ginseng saponin at a rate of 100 ${\mu}g$/6.2 ml/20 min, respectively. Pretreatment with total ginseng saponin also depressed greatly high potassium (56 mM, a membrane depolarizing agent)- and Bay-K-8644 (10 ${\mu}M$, a calcium channel activator)-induced CA secretions. Taken together, it is thought that total ginseng saponin can inhibit the releasing effect of CA evoked by nicotinic receptor stimulation from the isolated perfused rat adrenal medulla, which seems to be associated to the direct inhibition of influx through L-type calcium channel into the rat adrenomedullary chromaffin cells. It seems that there is species differences in the adrenomedullary catecholamine secretion between the rabbit and rat.

• Journal of Ginseng Research
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• 제45권6호
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• pp.683-694
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• 2021

Background: Ginsenoside Rg1 (Rg1) has been well documented to be effective against various cardiovascular disease. The aim of this study is to evaluate the effect of Rg1 on mechanical stress-induced cardiac injury and its possible mechanism with a focus on the calcium sensing receptor (CaSR) signaling pathway. Methods: Mechanical stress was implemented on rats through abdominal aortic constriction (AAC) procedure and on cardiomyocytes and cardiac fibroblasts by mechanical stretching with Bioflex Collagen I plates. The effects of Rg1 on cell hypertrophy, fibrosis, cardiac function, [Ca²⁺]_i, and the expression of CaSR and calcineurin (CaN) were assayed both on rat and cellular level. Results: Rg1 alleviated cardiac hypertrophy and fibrosis, and improved cardiac decompensation induced by AAC in rat myocardial tissue and cultured cardiomyocytes and cardiac fibroblasts. Importantly, Rg1 treatment inhibited CaSR expression and increase of [Ca²⁺]_i, which similar to the CaSR inhibitor NPS2143. In addition, Rg1 treatment inhibited CaN and TGF-b1 pathways activation. Mechanistic analysis showed that the CaSR agonist GdCl₃ could not further increase the [Ca²⁺]_i and CaN pathway related protein expression induced by mechanical stretching in cultured cardiomyocytes. CsA, an inhibitor of CaN, inhibited cardiac hypertrophy, cardiac fibrosis, [Ca²⁺]_i and CaN signaling but had no effect on CaSR expression. Conclusion: The activation of CaN pathway and the increase of [Ca²⁺]_i mediated by CaSR are involved in cardiac hypertrophy and fibrosis, that may be the target of cardioprotection of Rg1 against myocardial injury.

• International Journal of Oral Biology
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• 제46권4호
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• pp.176-183
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• 2021

Oral squamous cell carcinoma (OSCC) metastasis is characterized by distant metastasis and local recurrence. Combined chemotherapy with cisplatin and 5-fluorouracil is routinely used to treat patients with OSCC, and the combined use of gefitinib with cytotoxic drugs has been reported to enhance the sensitivity of cancer cells in vitro. However, the development of drug resistance because of prolonged chemotherapy is inevitable, leading to a poor prognosis. Therefore, understanding alterations in signaling pathways and gene expression is crucial for overcoming the development of drug resistance. However, the altered characterization of Ca²⁺ signaling in drug-resistant OSCC cells remains unclear. In this study, we investigated alterations in intracellular Ca²⁺ ([Ca²⁺]_i) mobilization upon the development of gefitinib resistance in human tongue squamous carcinoma cell line (HSC)-3 and HSC-4 using ratiometric analysis. This study demonstrated the presence of altered epidermal growth factor- and purinergic agonist-mediated [Ca²⁺]_i mobilization in gefitinib-resistant OSCC cells. Moreover, Ca²⁺ content in the endoplasmic reticulum, store-operated calcium entry, and lysosomal Ca²⁺ release through the transient receptor potential mucolipin 1, were confirmed to be significantly reduced upon the development of apoptosis resistance. Consistent with [Ca²⁺]_i mobilization, we identified modified expression levels of Ca²⁺ signaling-related genes in gefitinib-resistant cells. Taken together, we propose that the regulation of [Ca²⁺]_i mobilization and related gene expression can be a new strategy to overcome drug resistance in patients with cancer.

• The Korean Journal of Physiology and Pharmacology
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• 제18권4호
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• pp.297-305
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• 2014

Flavonoids have an ability to suppress various ion channels. We determined whether one of flavonoids, cyanidin-3-glucoside, affects adenosine 5'-triphosphate (ATP)-induced calcium signaling using digital imaging methods for intracellular free $Ca^{2+}$ concentration ([$Ca^{2+}$]i), reactive oxygen species (ROS) and mitochondrial membrane potential in PC12 cells. Treatment with ATP ($100{\mu}M$) for 90 sec induced [$Ca^{2+}$]i increases in PC12 cells. Pretreatment with cyanidin-3-glucoside ($1{\mu}g/ml$ to $100{\mu}g/ml$) for 30 min inhibited the ATP-induced [$Ca^{2+}$]i increases in a concentration-dependent manner ($IC_{50}=15.3{\mu}g/ml$). Pretreatment with cyanidin-3-glucoside ($15{\mu}g/ml$) for 30 min significantly inhibited the ATP-induced [$Ca^{2+}$]i responses following removal of extracellular $Ca^{2+}$ or depletion of intracellular [$Ca^{2+}$]i stores. Cyanidin-3-glucoside also significantly inhibited the relatively specific P2X2 receptor agonist 2-MeSATP-induced [$Ca^{2+}$]i responses. Cyanidin-3-glucoside significantly inhibited the thapsigargin or ATP-induced store-operated calcium entry. Cyanidin-3-glucoside significantly inhibited the ATP-induced [$Ca^{2+}$]i responses in the presence of nimodipine and ${\omega}$-conotoxin. Cyanidin-3-glucoside also significantly inhibited KCl (50 mM)-induced [$Ca^{2+}$]i increases. Cyanidin-3-glucoside significantly inhibited ATP-induced mitochondrial depolarization. The intracellular $Ca^{2+}$ chelator BAPTA-AM or the mitochondrial $Ca^{2+}$ uniporter inhibitor RU360 blocked the ATP-induced mitochondrial depolarization in the presence of cyanidin-3-glucoside. Cyanidin-3-glucoside blocked ATP-induced formation of ROS. BAPTA-AM further decreased the formation of ROS in the presence of cyanidin-3-glucoside. All these results suggest that cyanidin-3-glucoside inhibits ATP-induced calcium signaling in PC12 cells by inhibiting multiple pathways which are the influx of extracellular $Ca^{2+}$ through the nimodipine and ${\omega}$-conotoxin-sensitive and -insensitive pathways and the release of $Ca^{2+}$ from intracellular stores. In addition, cyanidin-3-glucoside inhibits ATP-induced formation of ROS by inhibiting $Ca^{2+}$-induced mitochondrial depolarization.

• BMB Reports
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• 제29권1호
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• pp.11-16
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• 1996

The present study showed that receptor-mediated activation of rabbit kidney proximal tubule cells by angiotensin II, the $Ca^{2+}$ ionophore A23187, or the protein kinase C activator phorbol myristate acetate (PMA) all stimulated phospholipase D (PLD). This was demonstrated by the increased formation of phosphatidic acid, and in the presence of 0.5% ethanol, phosphatidylethanol (PEt) accumulation. Angiotensin II leads to a rapid increase in phosphatidic acid and diacylglycerol, and phosphatidic acid formation preceeded the formation of diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine hydrolyzed by Pill. On the other hand, EGTA substantially attenuated angiotensin II and A23187-induced PEt formation, and when the cells were pretreated with verapamil angiotensin II-induced Pill activation was completely abolished. These results provide the evidence that calcium ion influx is essential for the agonist-induced Pill activation. In addition, staurosporine, an inhibitor of protein kinase C, strongly inhibited PMA-induced PEt formation, but was ineffective on angiotensin II-induced PEt accumulation. $GTP{\gamma}S$ also stimulates PEt formation in digitonin-permeabilized cells, but pretreatment of the cells with pertussis toxin failed to suppress angiotensin II-induced PEt formation. From these results, we conclude that in the rabbit kidney proximal tubule cells the mechanisms of angiotensin II- and PMA-induced Pill activation are different from each other and mediated via a pertussis toxin-insensitive trimeric G protein.