• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.109-114
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• 2005

Ion fluxes across the plasma membrane activated by 1 mM $Ce^{4+}$, cell apoptosis and taxol biosynthesis in suspension cultures of Taxus cusp/data were studied. The extracellular pH sharply decreased upon the addition of 1 mM $Ce^{4+}$, then increased gradually and exceeded the initial pH value over a time period of 12 h. The extracellular $Ca^{2+}$ concentration decreased within the first 3 h after the addition of $Ce^{4+}$, then gradually decreased to one third of initial value in control at about 72 h and remained unchanged afterwards. Experiments with an ion channel blocker and a $Ca^{2+}$-channel blocker indicated that the dynamic changes in extracellular pH and the $Ca^{2+}$ concentration resulted from the $Ce^{4+}$-induced activation of W uptake and $Ca^{2+}$ influx across the plasma membrane via ion channels. A pretreatment of the ion channel blocker initiated $Ce^{4+}$-treated cells to undergo necrosis, and the prior addition of the $Ca^{2+}$-channel blocker inhibited $Ce^{4+}$-induced taxol biosynthesis and apoptosis. It is thus inferred that W uptake is necessary for cells to survive a $Ce^{4+}$-caused acidic environment and is one of the mechanisms of $Ce^{4+}$-induced apoptosis. Furthermore, the $Ca^{2+}$ influx across the plasma membrane mediated both the $Ce^{4+}$-induced apoptosis and taxol biosynthesis.

• Molecules and Cells
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• 제21권3호
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• pp.418-427
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• 2006

Ionotropic glutamate receptors (iGluRs) are ligand-gated nonselective cation channels that mediate fast excitatory neurotransmission. Although homologues of the iGluRs have been identified in higher plants, their roles are largely unknown. In this work we isolated a full-length cDNA clone (RsGluR) encoding a putative glutamate receptor from small radish. An RsGluR:mGFP fusion protein was localized to the plasma membrane. In Arabidopsis thaliana overexpressing the fulllength cDNA, glutamate treatment triggered greater $Ca^{2+}$ influx in the root cells of transgenic seedlings than in those of the wild type. Transgenic plants exhibited multiple morphological changes such as necrosis at their tips and the margins of developing leaves, dwarf stature with multiple secondary inflorescences, and retarded growth, as previously observed in transgenic Arabidopsis overexpressing AtGluR3.2 [Kim et al. (2001)]. Microarray analysis showed that jasmonic acid (JA)-responsive genes including defensins and JA-biosynthetic genes were up-regulated. RsGluR overexpression also inhibited growth of a necrotic fungal pathogen Botrytis cinerea possibly due to up-regulation of the defensins. Based on these results, we suggest that RsGluR is a glutamate-gated $Ca^{2+}$ channel located in the plasma membrane of higher plants and plays a direct or indirect role in defense against pathogen infection by triggering JA biosynthesis.

• 한국동물학회:뉴스레터
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• 제12권2호
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• pp.109.1-109
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• 1995

No Abstract, See Full Text

• 동의생리병리학회지
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• 제19권5호
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• pp.1311-1316
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• 2005

This study was designed to potentiate the vasodilation effect of Banhabackchulchunma-Tang(BCT) prescription by change of mixture. Six different BCT compositions were made according to mixture of herbs. The vascular relaxation effects of 6 different BCT compositions were examined on phenylephrine(PE)-precontracted rat thoracic aorta. The BCT-1 composition exerted significant relaxation on phenylephrine- or KCI- contracted rat thoracic aorta. Its elaxation was endothelium- independent in both PE- and KCl-induced contraction. Treatment of glibenclamide or tetraethylammonium(TEA) did not affect the relaxation of BCT-1. Vasorelaxation efficacy of BCT-1 was also not influenced by low (25mM) or high (50mM, 80mM) KCl-induced contraction. Furthermore, the contraction by increasing $Ca^{2+}$ concentrations (0.3-10.0mM) to a $Ca^{2+}$-free high K+ (60mM) was significantly reduced by pretreatment with BCT-1 In addition, the relaxant effects were not inhibited by pretreatment of rat aorta with L-NAME, MB, indomethacin and atropine. These results confirm that BCT-1 may exerts its vasodilation effect by endothelium-independent manner. According to the above results, we suggest that the relaxation effect of BCT-1 is endothelium-independent and is related with block of $Ca^{2+}$ influx via $Ca^{2+}$ channel.

• Journal of Microbiology
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• 제34권3호
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• pp.253-269
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• 1996

Infection of fish cells with IHNV resulted in gradual increase in cytosolic free Ca$\^$2+/ concentration ([Ca$\^$2+/)] in CHSE, gradual decrease in [Ca$\^$2+/] in FHM, and no significant change in RTG cells. The degree of [Ca$\^$2+/] increase or decrease was dependent on the amount of infectious virus, and these [Ca$\^$2+/] variations were maximal at 16 hours after virus infection (p. i.) in both cell lines. When the fish cells were infected with inactivated IHNV, evident variation in [Ca$\^$2+/] was not observed. Thus, infectivity of IHNV appears to correlate with changes in [Ca$\^$2+/] in virus-infected cells. These IHNV-induced [Ca$\^$2+/] changes were partially blocked by cycloheximide, but not affected by cordycepin. It seems to be that virus-induced Ca$\^$2+/ variations were more related with protein synthesis than RNA synthesis. Various Ca$\^$2+/ related drugs were used in search for the mechanisms of the [Ca$\^$2+/], changes following IHNV infection of CHSE cells. Decreasing extracellular Ca$\^$2+/ concentration or blocking Ca$\^$2+/ influx from extracellular media inhibited the IHNV-induced increase in [Ca$\^$2+/], in CHSE cells. Similar results were obtained with intracellular Ca$\^$2+/ sources are important in IHNV-induced [Ca$\^$2+/] increase in CHSE cells.

• Journal of Ginseng Research
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• 제24권3호
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• pp.138-142
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• 2000

흰쥐 대뇌겉질로부터 별아교세포를 배양하여 흥분성아미노산인 L-glutamate에 의하여 유발되는 세포종창(astrocytic swelling)에 대한 ginsenosides의 억제효과를 검토하였다. Glutamate(0.5 mM)를 세포에 가하고 1시간동안 배양하면 swelling을 일으켜, 세포내의 물의 용적([$^3$H]OMG의 uptake량으로 측정)은 대조세포에 비하여 약 2배의 증가를 나타냈다. Glutamate와 함께 ginsenosides Rb$_2$와 Rc를 가하고 배양하면 glutamate에 의한 astrocytic swelling이 용량의존적으로 감소하였다. 세포는 Rb$_2$와 Rc(0.5 mg/ml)에 24시간까지 노출시켜도 MTT reduction이 감소하지 않는 것으로 보아 이 ginsenosides에 의한 swelling의 억제효과는 세포막의 손상에 의한 것이 아님을 알 수 있었다. Rb$_2$와 Rc는 glutamate에 의한 세포내 $Ca^{2+}$농도의 상승을 억제하였다. 따라서 Rb$_2$와 Rc는Ca$^{2+}$의 유입을 억제하므로서 glutamate에 의한 astrocytic swelling을 억제하는 것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제13권3호
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• pp.175-179
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• 2009

High concentrations of ATP induce membrane blebbing. However, the underlying mechanism involved in epithelial cells remains unclear. In this study, we investigated the role of the P2X7 receptor (P2X7R) in membrane blebbing using Par C5 cells. We stimulated the cells with 5 mM of ATP for 1${\sim}$2 hrs and found the characteristics of membrane blebbing, a hallmark of apoptotic cell death. In addition, 500 ${\mu}M$ Bz-ATP, a specific P2X7R agonist, induced membrane blebbing. However, 300 ${\mu}M$ of Ox-ATP, a P2X7R antagonist, inhibited ATP-induced membrane blebbing, suggesting that ATP-induced membrane blebbing is mediated by P2X7R. We found that ATP-induced membrane blebbing was mediated by ROCK I activation and MLC phosphorylation, but not by caspase-3. Five mM of ATP evoked a biphasic $[Ca^{2+}]_i$ response; a transient $[Ca^{2+}]_i$ peak and sustained $[Ca^{2+}]_i$ increase secondary to ATP-stimulated $Ca^{2+}$ influx. These results suggest that P2X7R plays a role in membrane blebbing of the salivary gland epithelial cells.

• International Journal of Oral Biology
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• 제49권1호
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• pp.10-17
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• 2024

Glutamate-mediated oxidative stress causes neuronal cell death by increasing intracellular Ca²⁺ uptake, reactive oxidative species (ROS) generation, mitogen-activated protein kinase (MAPK) activation, and translocation of apoptosis-inducing factor (AIF) to the nucleus. In the current study, we demonstrated that corydaline exerts potent neuroprotective effects against glutamate-induced neurotoxicity. Treatment with 5 mmol/L glutamate increased cellular Ca²⁺ influx, ROS generation, MAPK activation, and AIF translocation. In contrast, corydaline treatment decreased cellular Ca²⁺ influx and ROS generation. Western blot analysis revealed that glutamate-mediated MAPK activation was attenuated by corydaline treatment. We further demonstrated that corydaline treatment inhibited the glutamate-mediated translocation of AIF to the nucleus. We propose that corydaline is a promising lead structure for the development of safe and effective neuroprotectants.

• Journal of Photoscience
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• 제3권3호
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• pp.127-132
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• 1996

Calcium has a variety of functions in neuron and muscle cells and blood clotting, especially in the visual system where dark adapted rods cotransport with Na$^+$ into the cell. An influx of Ca$^{2+}$ flows out of the cell through the Na$^+$ - Ca$^{2+}$ exchanger. By using a modified Ussing chamber in order to bring in vivo environment close, we have concluded that Ca$^{2+}$ blocks the activity of guanylate cyclase; in consequence, having an effect on the amplitude of electroretinogram (ERG). We suggest that Ca$^{2+}$ moves between the photoreceptor and the vitreous humor by way of certain Ca$^{2+}$ transport mechanisms. Also, the effect of Zn$^{2+}$ in Ca$^{2+}$ - free ringer solution caused an elevation of amplitude in ERG and a reduction of threshold.

• Journal of Ginseng Research
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• 제42권4호
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• pp.470-475
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• 2018

Background: It was previously found that Korean Red Ginseng water extract (KRGE) inhibits the histamine-induced itch signaling pathway in peripheral sensory neurons. Thus, in the present study, we investigated whether KRGE inhibited another distinctive itch pathway induced by chloroquine (CQ); a representative histamine-independent pathway mediated by MrgprA3 and TRPA1. Methods: Intracellular calcium changes were measured by the calcium imaging technique in the HEK293T cells transfected with both MrgprA3 and TRPA1 ("MrgprA3/TRPA1"), and in primary culture of mouse dorsal root ganglia (DRGs). Mouse scratching behavior tests were performed to verify proposed antipruritic effects of KRGE and ginsenoside Rg3. Results: CQ-induced $Ca^{2+}$ influx was strongly inhibited by KRGE ($10{\mu}g/mL$) in MrgprA3/TRPA1, and notably ginsenoside Rg3 dose-dependently suppressed CQ-induced $Ca^{2+}$ influx in MrgprA3/TRPA1. Moreover, both KRGE ($10{\mu}g/mL$) and Rg3 ($100{\mu}M$) suppressed CQ-induced $Ca^{2+}$ influx in primary culture of mouse DRGs, indicating that the inhibitory effect of KRGE was functional in peripheral sensory neurons. In vivo tests revealed that not only KRGE (100 mg) suppressed CQ-induced scratching in mice [bouts of scratching: $274.0{\pm}51.47$ (control) vs. $104.7{\pm}17.39$ (KRGE)], but also Rg3 (1.5 mg) oral administration significantly reduced CQ-induced scratching as well [bouts of scratching: $216.8{\pm}33.73$ (control) vs.$115.7{\pm}20.94$ (Rg3)]. Conclusion: The present study verified that KRGE and Rg3 have a strong antipruritic effect against CQ-induced itch. Thus, KRGE is as a promising antipruritic agent that blocks both histamine-dependent and -independent itch at peripheral sensory neuronal levels.