• The Korean Journal of Physiology and Pharmacology
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• v.8 no.6
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• pp.313-317
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• 2004

The present study were designed to characterize the action mechanisms of acetylcholine (ACh)-induced endothelium-dependent relaxation in arteries precontracted with high $K^+$(70 mM). For this, we simultaneously measured both muscle tension and cytosolic free $Ca^{2+}$ concentration $([Ca^{2+}]_i)$, using fura-2, in endothelium-intact, rabbit carotid arterial strips. In the artery with endothelium, high $K^+$ increased both $[Ca^{2+}]_i$ and muscle tension whereas ACh $(10{\mu}M)$ significantly relaxed the muscle and increased $[Ca^{2+}]_i$. In the presence of $N^G$-nitro-L-arginine (L-NAME, 0.1 mM), ACh increased $[Ca^{2+}]_i$ without relaxing the muscle. In the artery without endothelium, high $K^+$ increased both $[Ca^{2+}]_i$ and muscle tension although ACh was ineffective. 4-DAMP (10 nM) or atropine $(0.1{\mu}M)$ abolished ACh-induced increase in $[Ca^{2+}]_i$ and relaxation. The increase of $[Ca^{2+}]_i$ and vasorelaxation by ACh was siginificantly reduced by either $3{\mu}M$ gadolinium, $10{\mu}M$ lanthanum, or by $10{\mu}M$ SKF 96365. These results suggest that in rabbit carotid artery, ACh-evoked relaxation of 70 mM $K^+$-induced contractions appears to be mediated by the release of NO. ACh-evoked vasorelaxation is mediated via the $M_3$ subtype, and activation of the $M_3$ subtype is suggested to stimulate nonselective cation channels, leading to increase of $[Ca^{2+}]_i$ in endothelial cells.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1053-1062
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• 2007

In the present work, we show that tamoxifen(Tam)-induced cytotoxicity is due to the mitochondrial-dependent pathway triggered by the intracellular $Ca^{2+}$ increase in MCF-7 human breast cancer cells. Tam induced the intracellular $Ca^{2+}$ increase. According to the experimental results with $Ca^{2+}$ channel blockers, Tam-induced $Ca^{2+}$ uptake seemed to depend on the voltage-sensitive $Ca^{2+}$ channel at the early stage, but at later stages the intracellular $Ca^{2+}$ increases are more likely due partly to the release of stored $Ca^{2+}$ and partly to the capacitative $Ca^{2+}$ or other entry pathways. Tam-induced $Ca^{2+}$ increase led to the release of cytochrome c from mitochondria into the cytosol and the change of mitochondrial membrane potential. In MCF-7 cells, caspase-7 plays a key role in the downstream of apoptosis because caspase-3 is absent. In the cells treated with Tam, caspase-7 cleavage was increased almost two-fold. There was no marked alteration in the level of anti-apoptotic Bcl-2 protein; however, the cells showed increased expression of pro-apoptotic Bax protein more than two-fold in response to Tam. These results imply that the apoptotic signaling pathway activated by Tam is likely to be mediated via the mitochondrial-dependent pathway.

• Proceedings of the Ginseng society Conference
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• 1984.09a
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• pp.191-197
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• 1984

A further purified fraction (D-O-ANa) was obtained from DPG 3-2 fraction of Ginseng Radix by complete removal of saponins, nucleosides, nucleic acid bases, amino acids, and sugars. D-O-ANa - induced insulin release was investigated to compare with that of DPG 3-2 and other isolated components. Among the sub fractions of DPG 3-2, D-O-ANa exhibited the most potent release of insulin with or without high concentrations of glucose, and it particularly enhanced the second phase of glucose-induced insulin release. DGP 3-2 potentiated significantly the glucose-induced insulin release from the isolated islets of diabetic mice at increasing concentrations of extracellular calcium ions (0.16 - 2.5 mM). A definite relationship was found between calcium $(^{45}Ca)$ uptake and insulin release. Ginsenoside $(G)-Rb_1\;and\;G-Rg_1$ did not enhance the glucose-induced insulin release. The effect of ginseng saponins was blocked by glucose (16.7 mM), being distinctly different from the glucose-potentiated effect of DPG 3-2. The insulin release effect of $G-Rg_1$ was unaffected by the presence or absence of extracellular $Ca^{2+}$ and theophylline. Adenosine also increased insulin release from isolated islets, but had no effect on perfused rat pancreas. Arginine stimulated insulin release less evidently than D-O-ANa, though arginineand adenosine-induced glucagon releases were more remarkable. In conclusion, D-O-ANa appears to be a major fraction in insulin release activity of ginseng and its mode of action may be related to $Ca^{2+}$ ion uptake. This physiological mechanism was distinct from that of the abnormal release induced by ginseng saponins.

• YAKHAK HOEJI
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• v.43 no.6
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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 orthodontics
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• v.19 no.1 s.27
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• pp.61-75
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• 1989

Recently, indirect evidences suggest that Na-Ca exchange mechanism is involved in bone resorption. To study this suggestion, effects of several drugs which increase the intracellular sodium concentration by different mechanisms on the PTH-induced bone resorption were analysed employing organ culture. Ulnae and radii were removed from 19-day fetal rats, prelabelled by subcutaneous injection of $200{\mu}\;Ci^{45}CaC1_2$ on the 17th day of gestation, and then explanted on the membrane filters in organ culture dishes. For studying the effects of amiloride, ouabain, monensin, and veratridine on the PTH-induced bone resorption, control group was cultured in BGJb media containing PTH (0.4U/ml) while experimental group was cultured in BGJb media containing PTH and drugs. The effects of drugs on the PTH-induced bone resorption were observed by the ratios of $\%-release$ of $^{45}Ca$ between paired control and experimental groups. The results were as follows: 1. $^{45}Ca$ release was significantly increased by PTH (0.4U/ml) at 48 and 72 hours of culture. 2. Amiloride, at concentration of $500{\mu}M$, significantly inhibited the PTH-induced bone resorption after 48 and 72 hours of culture. 3. Ouabain, at concentration of 0.1 mM, presented significant inhibition of PTH-induced bone resorption after 48 and 72 hours of culture, and at 0.5mM and 1mM, presented significant inhibition of PTH-induced bone resorption after 72 hours of culture. 4. Monensin, at concentration of 500nM, significantly inhibited PTH-induced bone resorption after 72 hours of culture. 5. Veratridine, at concentration of 0.5mM, presented significant inhibition of PTH-induced bone resorption after 48 and 72 hours of culture, and at 1mM, presented significant inhibition of PTH-induced bone resorption after 72 hours of culture. Taken altogether, these results suggest that Na-Ca exchange mechanism play a role in PTH-induced bone resolution.

• YAKHAK HOEJI
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• v.50 no.6
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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.

• Biomedical Science Letters
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• v.25 no.2
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• pp.123-130
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• 2019

Platelet aggregation is essential for hemostatic process in case of blood vessels damages. However, excessive platelet aggregation can cause cardiovascular disorders including atherosclerosis, thrombosis and myocardial infarction. Scopoletin is usually found in the roots of genus Scopolia or Artemisia, and is known to have anticoagulant and anti-malarial effects. This study investigated the effect of scopoletin on human platelet aggregation induced by U46619, an analogue of thromboxane $A_2(TXA_2)$. Scopoletin had anti-platelet effects by down-regulating $TXA_2$ and intracellular $Ca^{2+}$ mobilization ($[Ca^{2+}]_i$), the aggregation-inducing molecules generated in activated platelets. On the other hand, scopoletin increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are known to be intracellular $Ca^{2+}$ antagonists. This resulted in inhibition of fibrinogen binding to ${\alpha}IIb/{\beta}_3$ in U46619-induced human platelet aggregation. In addition, scopoletin inhibited the release of adenosine trisphosphate (ATP) in dose-dependent manner. This result means that the aggregation amplification activity through the granule secretion in platelets was suppressed by scopoletin. Therefore, we demonstrated that scopoletin has a potent antiplatelet effect and is highly likely to prevent platelet-derived vascular disease.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.181-190
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• 1992

The present study was conducted to investigate the effect of opioids on catecholamine (CA) secretion evoked by a selective cholinergic nicotinic agonist, 1,1-dimethyl-4-phenyl piperazinium (DMPP) and acetylcholine from the retrogradely perfused rat adrenal glands. Methionine-enkephalin $(9.68{\times}10^{-6}\;M)$ caused a significant inhibition of CA secretion evoked by DMPP (100 uM) and $ACh\;(50\;{\mu}g)$, but had no effect on the spontaneous (basal) CA release. Morphine $(1.73{\times}10^{-5}\;M)$ attenuated considerablely the increase in CA release induced by DMPP and ACh. Morphine itself also did not affect the basal CA output. A 20 to 65% reduction of the DMPP- and ACh-evoked increase in CA release was observed after the pretreatment with methionine-enkephalin or morphine. The increase in CA release evoked by DMPP and ACh was reduced markedly by preloading with an opiate antagonist naloxone $(1.22{\times}10^{-7}\;M)$ while basal CA output was not affected by naloxone. These present experimental results suggest that the nicotinic stimulation-evoked CA release from the perfused rat adrenal gland is inhibited by endogenously released opioid peptides through activation of opiate receptors located in the adrenal gland.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.797-801
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• 1997

Recently we reported that water extracts of Coptidis Rhizomas showed calcium antagonistic action and alpha-adrenoceptor inhibitory action in the vascular smooth muscle. Since ca lcium antagonistic properties are important in the treatment of various diseases including asthma. In the present study, the bronchodilatory effects of crude extract of three kinds of Coptidis Rhizoma (Coptidis chinensis, Coptis japonica and root hair of Coptis japonica) was investigated using rat isolated trachea. The result showed that all extracts relaxed carbachol-contracted tracheal smooth muscle. Concentration-dependently, in which the root hair of Coptis japonica was the least potent. The inhibitory potency expressed in terms of $IC_{50}$ against carbachol contraction was 1.8${\mu}$g/ml and 2.7${\mu}$g/ml for Coptidis chinensis and Coptis japonica, respectively. These extracts also inhibited KCI-contracted tracheal smooth muscle. But the relative potency ($IC_{50}$) was 3.5 and 4.1 folds weaker than carbachol-induced contraction for Coptidics chinenesis and Coptis japonica, respectively. Pretreatment of crude extracts also inhibited carbachol- or KCI-induced contraction, non-competitively. These findings indicate that the extracts have muscarinic blocking as well as $Ca^{2+}$ channel blocking action. When provoked intracellular stored $Ca^{2+}$ release by carbachol in $Ca^{2+}$-free conditions, initial phasic contraction due to $Ca^{2+}$ release was significantly inhibited by the extracts. As taken together, we conclude that water extracts of Coptidis Rhizoma may be beneficial in bronchospasm or other broncheal tube narrowing conditions such as asthma.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.197-201
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• 1988

Effects of high concentration of KC1 and caffeine on cytosolic $Ca^{2+}$ level $([Ca^{2+}]_{cyt})$, measured simultaneously with muscle tension using a fluorescent intracellular $Ca^{2+}$ indicator fura 2, were examined in isolated smooth muscle of rat aorta. High $K^+$ (72.7 mM) solution induced sustained increase in both $([Ca^{2+}]_{cyt})$ and tension. In contrast to this, caffeine (20 mM) induced a rapid increase in $([Ca^{2+}]_{cyt})$ followed by a decrease to a level which was higher than the resting level. However, muscle tension showed only a transient increase followed by a decrease below the resting level. In a $Ca^{2+}-free$ solution, high $K^+-induced$ neither $([Ca^{2+}]_{cyt})$ nor tension, whereas caffeine induced a transient increase in both $([Ca^{2+}]_{cyt})$ and muscle tension. These results suggest that high $K^+-induced$ contraction in vascular smooth muscle of rat aorta is due to $Ca^{2+}$ influx whereas caffeine-induced contraction is due to $Ca^{2+}$ release from cellular store. Further, caffeine seems to have an additional effect to decrease the sensitivity of the contractile elements to $Ca^{2+}$.