• The Korean Journal of Physiology and Pharmacology
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• v.9 no.1
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• pp.45-53
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• 2005

The present study was designed to examine the effect of d-amphetamine on CA release from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. Damphetamine $(10{\sim}100{\mu}M$), when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced the CA secretory responses evoked by ACh ($5.32{\times}10^{-3}$ M), excess $K^+$ ($5.6{\times}10^{-2}$ M, a membrane depolarizer), DMPP ($10^{-4}$ M, a selective neuronal nicotinic $N_n-receptor$ agonist) and McN-A-343 ($10^{-4}$ M, a selective $M_1-muscarinic$ agonist) only for the first period (4 min), although it alone has weak effect on CA secretion. Moreover, d-amphetamine ($30{\mu}M$) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$ ATPase only for the first period (4 min). However, in the presence of high concentration ($500{\mu}M$), d-amphetamine rather inhibited the CA secretory responses evoked by the above all of secretagogues. Collectively, these experimental results suggest that d-amphetamine at low concentrations enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization, but at high concentration it rather inhibits them. It seems that d-amphetamine has dual effects as both agonist and antagonist at nicotinic receptors of the isolated perfused rat adrenal medulla, which might be dependent on the concentration. It is also thought that these actions of d-amphetamine are probably relevant to the $Ca^{2+}$ mobilization through the dihydropyridine L-type $Ca^{2+}$ cha$N_n$els located on the rat adrenomedullary chromaffin cell membrane and the release of $Ca^{2+}$ from the cytoplasmic store.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.1
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• pp.27-32
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• 2009

The effects of oxidized low-density lipoprotein(OxLDL) and its major lipid constituent lysophosphatidylcholine(LPC) on $Ca^{2+}$ entry were investigated in cultured human umbilical endothelial cells(HUVECs) using fura-2 fluorescence and patch-clamp methods. OxLDL or LPC increased intracellular $Ca^{2+}$ concentration($[Ca^{2+}]_i$), and the increase of $[Ca^{2+}]_i$ by OxLDL or by LPC was inhibited by $La^{3+}$ or heparin. LPC failed to increase $[Ca^{2+}]_i$ in the presence of an antioxidant tempol. In addition, store-operated $Ca^{2+}$ entry(SOC), which was evoked by intracellular $Ca^{2+}$ store depletion in $Ca^{2+}$-free solution using the sarcoplasmic reticulum $Ca^{2+}$ pump blocker, 2, 5-di-t-butyl-l,4-benzohydroquinone(BHQ), was further enhanced by OxLDL or by LPC. Increased SOC by OxLDL or by LPC was inhibited by U73122. In voltage-clamped cells, OxLDL or LPC increased $[Ca^{2+}]_i$ and simultaneously activated non-selective cation(NSC) currents. LPC-induced NSC currents were inhibited by 2-APB, $La^{3+}$ or U73122, and NSC currents were not activated by LPC in the presence of tempol. Furthermore, in voltage-clamped HUVECs, OxLDL enhanced SOC and evoked outward currents simultaneously. Clamping intracellular $Ca^{2+}$ to 1 ${\mu}M$ activated large-conductance $Ca^{2+}$-activated $K^+(BK_{ca})$ current spontaneously, and this activated $BK_{ca}$ current was further enhanced by OxLDL or by LPC. From these results, we concluded that OxLDL or its main component LPC activates $Ca^{2+}$-permeable $Ca^{2+}$-activated NSC current and $BK_{ca}$ current simultaneously, thereby increasing SOC.

• BMB Reports
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• v.45 no.12
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• pp.742-747
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• 2012

Granulocyte colony-stimulating factor (G-CSF) is used for heart failure therapy and promotes myocardial regeneration by inducing mobilization of bone marrow stem cells to the injured heart after myocardial infarction; however, this treatment has one weakness in that its biological effect is transient. In our previous report, we generated 5 mutants harboring N-linked glycosylation to improve its antiapoptotic activities. Among them, one mutant (Phe140Asn) had higher cell viability than wild-type hG-CSF in rat cardiomyocytes, even after treatment with an apoptotic agent ($H_2O_2$). Cells treated with this mutant significantly upregulated the antiapoptotic proteins, and experienced reductions in caspase 3 activity and PARP cleavage. Moreover, the total number of apoptotic cells was dramatically lower in cultures treated with mutant hG-CSF. Taken together, these results suggest that the addition of an N-linked glycosylation was successful in improving the antiapoptotic activity of hG-CSF, and that this mutated product will be a feasible therapy for patients who have experienced heart failure.

• Biomolecules & Therapeutics
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• v.20 no.5
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• pp.463-469
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• 2012

Atopic dermatitis is a chronic, inflammatory disease of the skin with increased transepidermal water loss. Both an abnormal inflammatory response and a defective skin barrier are known to be involved in the pathogenesis of atopic dermatitis. Protease activated receptor 2 (PAR2) belongs to a family of G-protein coupled receptors and is activated by both trypsin and a specific agonist peptide, SLIGKV-$NH_2$. PAR2 is expressed in suprabasal layers of the epidermis and regulates inflammatory responses and barrier homeostasis. In this study, we show that nordihydroguaiaretic acid (NDGA) inhibits the PAR2-mediated signal pathway and plays a role in skin barrier recovery in atopic dermatitis. Specifically, NDGA reduces the mobilization of intracellular $Ca^{2+}$ in HaCaT keratinocytes by down-regulating inflammatory mediators, such as interleukin-8, thymus and activation-regulated chemokine and intercellular cell adhesion molecule-1 in HaCaT keratinocytes. Also, NDGA decreases the protein expression of involucrin, a differentiation maker of keratinocyte, in both HaCaT keratinocytes and normal human epidermal keratinocytes. We examined NDGA-recovered skin barrier in atopic dermatitis by using an oxazolone-induced atopic dermatitis model in hairless mice. Topical application of NDGA produced an increase in transepidermal water loss recovery and a decrease in serum IgE level, without weight loss. Accordingly, we suggest that NDGA acts as a PAR2 antagonist and may be a possible therapeutic agent for atopic dermatitis.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.3
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• pp.243-252
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• 2015

Melanosome, the pigment granule in melanocyte, determines the color of skin when it moves into the keratinocyte. Inhibition of melanosome transfer from melanocyte to keratinocyte results in skin depigmentation. Protease activated receptor-2 (PAR-2) is involved in signal transduction systems via cell membrane and increases the melasome transfer when it is activated by cleavage of their extracellular amino acid sequence by trypsin or by a peptide such as SLIGKV. Here, we showed that lobaric acid inhibited PAR-2 activation and affected the mobilization of $Ca2^+$. The uptake of fluorescent microspheres and isolated melanosomes from melan-a melanocytes to keratinocytes induced by SLIGKV were inhibited by lobaric acid. Also, confocal microscopy studies illustrated a decreased melanosome transfer to keratinocytes in melanocyte-keratinocyte co-culture system by lobaric acid. In addition, lobaric acid induced visible skin lightening effect in human skin tissue culture model, melanoderm$^{(R)}$. Our data suggest that lobaric acid could be an effective skin lightening agent that works via regulation of phagocytic activity of keratinocytes.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.3
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• pp.129-135
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• 2011

In this study we determined whether or not 5-hydroxytryptamine (5-HT) has an effect on the pacemaker activities of interstitial cells of Cajal (ICC) from the mouse small intestine. The actions of 5-HT on pacemaker activities were investigated using a whole-cell patch-clamp technique, intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) analysis, and RT-PCR in ICC. Exogenously-treated 5-HT showed tonic inward currents on pacemaker currents in ICC under the voltage-clamp mode in a dose-dependent manner. Based on RT-PCR results, we found the existence of 5-$HT_{2B,\;3,\;4,\;and\;7}$ receptors in ICC. However, SDZ 205557 (a 5-$HT_4$ receptor antagonist), SB 269970 (a 5-$HT_7$ receptor antagonist), 3-tropanylindole - 3 - carboxylate methiodide (3-TCM; a 5-$HT_3$ antagonist) blocked the 5-HT-induced action on pacemaker activity, but not SB 204741 (a 5-$HT_{2B}$ receptor antagonist). Based on $[Ca^{2+}]_i$ analysis, we found that 5-HT increased the intensity of $[Ca^{2+}]_i$. The treatment of PD 98059 or JNK II inhibitor blocked the 5-HT-induced action on pacemaker activity of ICC, but not SB 203580. In summary, these results suggest that 5-HT can modulate pacemaker activity through 5-$HT_{3,\;4,\;and\;7}$ receptors via $[Ca^{2+}]_i$ mobilization and regulation of mitogen-activated protein kinases.

• International Journal of Oral Biology
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• v.31 no.4
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• pp.127-133
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• 2006

[ $H_2O_2$ ], a member of reactive oxygen species (ROS), is known to be involved in the mediation of physiological functions in a variety of cell types. However, little has been known about the physiological role of $H_2O_2$ in exocrine cells. Therefore, in the present study, the effect of $H_2O_2$ on cholecystokinin (CCK)-evoked $Ca^{2+}$ mobilization and amylase release was investigated in rat pancreatic acinar cells. Stimulation of the acinar cells with sulfated octapeptide form of CCK (CCK-8S) induced biphasic increase in amylase release. Addition of $30\;{\mu}M\;H_2O_2$ enhanced amylase release caused by 10 pM CCK-8S, but inhibited the amylase release induced by CCK-8S at concentrations higher than 100 pM. An ROS scavenger, $10\;{\mu}M$ Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, increased amylase release caused by CCK-8S at concentrations higher than 100 pM, although lower concentrations of CCK-8S-induced amylase release was not affected. To examine whether the effect of $H_2O_2$ on CCK-8S-induced amylase release was exerted via modulation of intracellular $Ca^{2+}$ signaling, we measured the changes in intracellular $Ca^{2+}$ concentration $([Ca^{2+}]_i)$ in fura-2 loaded acinar cells. Although $30\;{\mu}M\;H_2O_2$ did not induce any increase in $[Ca^{2+}]_i$ by itself, it increased the frequency and amplitude of $[Ca^{2+}]_i$ oscillations caused by 10 pM CCK-8S. However, $30\;{\mu}M\;H_2O_2$ had little effect on 1 nM CCK-8S-induced increase in $[Ca^{2+}]_i$. ROS scavenger, 1 mM N-acetylcysteine, did not affect $[Ca^{2+}]_i$ changes induced by 10 pM or 1 nM CCK-8S. Therefore, it was concluded that $30\;{\mu}M\;H_2O_2$ enhanced low concentration of CCK-8S-induced amylase release probably by increasing $[Ca^{2+}]_i$ oscillations while it inhibited high concentration of CCK-8S-induced amylase release.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.293-303
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• 1990

The contractile action of barium $(Ba^{2+})$ was investigated in the arterial strip of rabbit renal artery. The helical strip of isolated renal artery was immersed in the Tris-buffered Tyrode's solution equilibrated with 100% $O_2$ at $37^{\circ}C$ and its isometric tension was measured. $Ba^{2+}-induced$ contraction of arterial strip was dose-dependent and its maximal tension corresponded to $92.1{\pm}4.5%$ of tension by $K^+(100\;mM)$. $Ba^{2+}-induced$ contraction did not show the tachyphylactic phenomenon in the normal Tyrode's solution. $Ba^{2+}$ induced the tonic contraction in the $Ca^{2+}-free$ tyrode's solution and that was increased by the extracellula addition of $Ca^{2+}$. During the repeated exposure of the same dose of $Ba^{2+}\;(10\;mM)$ in the $Ca^{2+}-free$ Tyrode's solution, $Ba^{2+}-induced$ contraction was progressively decreased. Even though the intracellular NE-and caffeine-sensitive $Ca^{2+}$ was depleted, $Ba^{2+}$ induced the tonic contraction. After the pretreatment of lanthnum or verapamil, $Ba^{2+}$ did not induce contraction. $Ba^{2+}-induced$contraction was suppressed by extracellular $K^+$ in the normal Tyrode's solution and that was dependent on $K^+$ concentration. Suppressive effect of $K^+\;(14\;mM)$ on the $Ba^{2+}-induced$ contraction was also dependent on the intracellular $Ca^{2+}$ concentration. From the above resuts, it is suggested that $Ba^{2+}$ activate indirectly the contractile process by promoting the mobilization of intracellular $Ca^{2+}$ and the influx of extracellular $Ca^{2+}$. It is also suggested that action of $Ba^{2+}$ on the $Ca^{2+}-activated$ $K^+$ channel can result in the depolarization of cell membrane in the rabbit renal artery.

• Journal of Gastric Cancer
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• v.21 no.2
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• pp.191-202
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• 2021

Purpose: A near-infrared (NIR) fluorescence imaging is a promising tool for cancer-specific image guided surgery. Human epidermal receptor 2 (HER2) is one of the candidate markers for gastric cancer. In this study, we aimed to synthesize HER2-specific NIR fluorescence probes and evaluate their applicability in cancer-specific image-guided surgeries using an animal model. Materials and Methods: An NIR dye emitting light at 800 nm (IRDye800CW; Li-COR) was conjugated to trastuzumab and an HER2-specific affibody using a click mechanism. HER2 affinity was assessed using surface plasmon resonance. Gastric cancer cell lines (NCI-N87 and SNU-601) were subcutaneously implanted into female BALB/c nu (6-8 weeks old) mice. After intravenous injection of the probes, biodistribution and fluorescence signal intensity were measured using Lumina II (Perkin Elmer) and a laparoscopic NIR camera (InTheSmart). Results: Trastuzumab-IRDye800CW exhibited high affinity for HER2 (K_D=2.093(3) pM). Fluorescence signals in the liver and spleen were the highest at 24 hours post injection, while the signal in HER2-positive tumor cells increased until 72 hours, as assessed using the Lumina II system. The signal corresponding to the tumor was visually identified and clearly differentiated from the liver after 72 hours using a laparoscopic NIR camera. Affibody-IRDye800CW also exhibited high affinity for HER2 (K_D=4.71 nM); however, the signal was not identified in the tumor, probably owing to rapid renal clearance. Conclusions: Trastuzumab-IRDye800CW may be used as a potential NIR probe that can be injected 2-3 days before surgery to obtain high HER2-specific signal and contrast. Affibody-based NIR probes may require modifications to enhance mobilization to the tumor site.

• Journal of Life Science
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• v.28 no.5
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• pp.621-626
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• 2018

We introduced the physiological responses of aging, active aging and also suggest the impact of physical exercise on body health status and elderly immunity. In this purpose, we searched the Pub Med data base for the articles (include our experimental papers) and review papers having the terms 'Aging', 'Active aging' and 'Physical activity and elderly' in the title, published from 1999 until 2018. The results were as follows: Exercise training has been extensively studied about the reduction of inflammation, oxidative stress, disease, and aging in syndrome X patients and elderly. Combined and aerobic or resistance exercise training could reduce obesity, insulin resistance, type 2 diabetes and hypertension. Exercise training has been extensively studied in cancer settings as part of prevention or treatment strategies. From this research, regular exercise has the potential to target tumor growth through regulation of inflammation and immune responses such as lactate clearance, NK cell activation (innate immunity), activation of cytotoxic immune cells, T cell activation (adaptive immunity), and immune surveillance. However, Endurance physical activity not only induces thermogenesis and diverse sports injuries but also elicits mobilization and functional enhancement of monocytes, neutrophils (which is caused by the cytokine changes such as TNF-alpha, IL-1) whereas it suppresses cell mediated immunity causing to increased susceptibility to inflammation and infections like cough and URTIs (upper respiratory track infections) in young and especially in elderly people. Therefore, Strategies to prevent physical fatigue, sports injuries include avoid overtraining, Adequate recovery and various type of rest during and after physical activity and assuring adequate nutrition supplementation such as glutamine, vitamin B, vitamin C, carbohydrate, ion or berry-contain sports beverages is helpful in physically active elderly.