• The Korean Journal of Physiology and Pharmacology
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• 제3권1호
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• pp.1-10
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• 1999

We sought to find out the mechanism of vascular relaxation by extracellular $K^+$ concentration $([K^+]_o)$ in the cerebral resistant arteriole from rabbit. Single cells were isolated from the cerebral resistant arteriole, and using voltage-clamp technique barium-sensitive $K^+$ currents were recorded, and their characteristics were observed. Afterwards, the changes in membrane potential and currents through the membrane caused by the change in $[K^+]_o$ was observed. In the smooth muscle cells of cerebral resistant arteriole, ion currents that are blocked by barium, 4-aminopyridine (4-AP), and tetraethylammonium (TEA) exist. Currents that were blocked by barium showed inward rectification. When the $[K^+]_o$ were 6, 20, 60, and 140 mM, the reversal potentials were $-82.7{\pm}1.0,\;-49.5{\pm}1.86,\;-26{\pm}1.14,\;-5.18{\pm}1.17$ mV, respectively, and these values were almost identical to the calculated $K^+$ equilibrium potential. The inhibition of barium-sensitive inward currents by barium depended on the membrane potential. At the membrane potentials of -140, -100, and -60 mV, $K_d$ values were 0.44, 1.19, and 4.82 ${\mu}M,$ respectively. When $[K^+]_o$ was elevatedfrom 6 mM to 15 mM, membrane potential hyperpolarized to -50 mV from -40 mV. Hyperpolarization by $K^+$ was inhibited by barium but not by ouabain. When the membrane potential was held at resting membrane potential and the $[K^+]_o$ was elevated from 6 mM to 15 mM, outward currents increased; when elevated to 25 mM, inward currents increased. Fixing the membrane potential at resting membrane potential and comparing the barium-sensitive outward currents at $[K^+]_o$ of 6 and 15 mM showed that the barium- sensitive outward current increased at 15 mM $K^+.$ From the above results the following were concluded. Barium-sensitive $K^+$?channel activity increased when $[K^+]_o$ is elevated and this leads to an increase in $K^+-outward$ current. Consequently, the membrane potential hyperpolarizes, leading to the relaxation of resistant arteries, and this is thought to contribute to an increase in the local blood flow of brain.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.23-23
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• 2003

It has been suggested that the impairment of smooth muscle cell (SMC) function by alterations in the $Ca^{2+}$-activated $K^{+}$ ( $K_{Ca}$ ) channels accounts for the reduction in coronary reserve during left ventricular hypertrophy (LVH). However, this hypothesis has not been fully investigated. The main goal of this study was to assess whether the properties of $K_{Ca}$ channels in coronary SMCs were altered during LVH. New Zealand white rabbits (0.8-1.0 kg) and Sprague-Dawley rats (300-400 g) were randomly selected to receive either an injection of isoproterenol (300 $\mu\textrm{g}$/kg body weight) or an equal volume of 0.9％ saline (1 mL/kg body weight). The animals developed LVH 10 days after injection. In patch-clamp experiments, the unitary current amplitude and open probability for the $K_{Ca}$ channels were significantly reduced in LVH patches compared with control patches. The concentration-response curve of the $K_{Ca}$ channel to [C $a^{2+}$]$_{i}$ was shifted to the right. Inhibition of the $K_{Ca}$ channels with TEA was more pronounced in LVH cells than in the control cells. The whole-cell currents of $K_{Ca}$ channels were reduced during LVH. Western blot analysis indicated no differences in $K_{Ca}$ channel expression between the control and LVH coronary SM membranes. In contraction experiments, the effect of a high $K^{+}$concentration on the resting tension of the LVH coronary artery was greater than on that of the control. The effect of TEA on the resting tension of the LVH coronary artery was reduced as compared with the effect on the control. Our findings imply a novel mechanism for reduced coronary reserve during LVH.ing LVH.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 전기 한국발생생물학회 제16차 학술대회논문집
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• pp.21-23
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• 2003

Mechanisms regulate the arrest and growth of the resting primordial follicles are very poorly understood. To elucidate genes involved in the early folliculogenesis, we conducted suppression subtractive hybridization using mRNA from day1 and day5 ovaries and selected weel for further analysis, since it was most frequent gene in the day1-subtracted cDNA library (1). Expression of weel and correlated components of the cell cycle machinery, such as cdc2, cyclin B1, cdc25C, and phosphorylated cdc2 was evaluated by immunohistochemistry. In primordial follicles, expression of weel, cdcw, and cyclin B1 was cytoplasmic in oocytes, but phosphorylated cdc2 was weakly expressed in oocytes. While cdc25C expression was in ovarian somatic and in some theca cells. None of components was expressed in the pre-granulosa cells of the primordial follicles, while weel weakly, and cdc2 and cyclin B1 was strongly expressed in the granulosa cells of the growing follicles. Results from the present study suggest that 1) the mejotic arrest of the oocytes may not due to of cell cycle machinery, and 2) the weel may arrest meiosis by sequestering cdc2 and cyclin B1 in the cytoplasm by protein-protein interactions and/or by inhibitory phosphorylation.

• Molecules and Cells
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• 제24권2호
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• pp.261-267
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• 2007

Apoptotic signals are typically accompanied by activation of aspartate-specific cysteine proteases called caspases, and caspase-3 and -7 play crucial roles in the execution of apoptosis. Previously, using the proteomic approach, protein disulfide isomerase (PDI) was found to be a candidate substrate of caspase-7. This abundant 55 kDa protein introduces disulfide bonds into proteins (via its oxidase activity) and catalyzes the rearrangement of incorrect disulfide bonds (via its isomerase activity). PDI is abundant in the ER but is also found in non-ER locations. In this study we demonstrated that PDI is cleaved by caspase-3 and -7 in vitro. In addition, in vivo experiment showed that it is cleaved during etoposide-induced apoptosis in HL-60 cells. Subcellular fractionation showed that PDI was also present in the cytosol. Furthermore, only cytosolic PDI was clearly digested by caspase-3 and -7. It was also confirmed by confocal image analysis that PDI and caspase-7 partially co-localize in both resting and apoptotic MCF-7 cells. Overexpression of cytosolic PDI (ER retention sequence deleted) inhibited cell death after an apoptotic stimulus. These data indicate that cytosolic PDI is a substrate of caspase-3 and -7, and that it has an anti-apoptotic action.

• The Korean Journal of Physiology and Pharmacology
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• 제11권1호
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• pp.15-20
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• 2007

To investigate whether hydrogen peroxide($H_2O_2$) affects intestinal motility, pacemaker currents and membrane potential were recorded in cultured interstitial cells of Cajal(ICC) from murine small intestine by using a whole-cell patch clamp. In whole cell patch technique at $30^{\circ}C$, ICC generated spontaneous pacemaker potential under current clamp mode(I=0) and inward currents(pacemaker currents) under voltage clamp mode at a holding potential of -70 mV. When ICC were treated with $H_2O_2$ in ICC, $H_2O_2$ hyperpolarized the membrane potential under currents clamp mode and decreased both the frequency and amplitude of pacemaker currents and increased the resting currents in outward direction under voltage clamp mode. Also, $H_2O_2$ inhibited the pacemaker currents in a dose-dependent manner. Because the properties of $H_2O_2$ action on pacemaker currents were same as the effects of pinacidil(ATP-sensitive $K^+$ channels opener), we tested the effects of glibenclamide(ATP-sensitive $K^+$ channels blocker) on $H_2O_2$ action in ICC, and found that the effects of $H_2O_2$ on pacemaker currents were blocked by co- or pre- treatment of glibenclamide. These results suggest that $H_2O_2$ inhibits pacemaker currents of ICC by activating ATP-sensitive $K^+$ channels.

• 한국수정란이식학회지
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• 제24권3호
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• pp.189-197
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• 2009

Two-pore domain 칼륨($K_{2P}$) 통로는 흥분세포 및 비흥분세포의 안정막 전압을 일정하게 유지하는데 관여한다. 그러나 생식세포 및 생식기관에서 발현되는 $K_{2P}$ 통로의 분포영역 및 그 기능에 대해서는 연구자들에 의해 아직 정리되지 못하였다. 본 종설에서는 $K_{2P}$ 통로의 생식세포 및 생식기관에서 발현, 분포 및 생리학적 의의를 논하였다. $K_{2P}$ 통로는 인간 영양막세포, 자궁근층, 태반혈관계, 자궁평활근조직, 태반융모조직 및 임신자궁조직에서 발현되어 임신에 있어서 관련성을 제시되었다. 또한, $K_{2P}$ 통로는 마우스 전핵배, 원숭이 정자 및 한우의 난소, 정소, 난자, 정자 및 수정란에서 발현 변화를 보였다. 특히, $K_{2P}$ 통로는 체외배양 시 변화되는 온도, 산소분압과 같은 배양조건에 의해 조절되는 특징을 보임으로써 수정 및 배 발달에 영향을 줄 수 있는 인자로 제시되었다. 그리고 $K_{2P}$ 통로는 과산화수소에 의해 유도된 마우스 전핵배의 세포 사멸에 있어서 칼륨 이온의 유출에 관여함이 확인되었다. $K_{2P}$ 통로의 생식세포 및 생식기관 내 발현 형태와 생리학적 특징은 생식생리학에 있어서 이온 통로 관련 기능들을 이해하는데 도움이 될 것이다.

• 대한한방종양학회지
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• 제6권1호
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• pp.67-79
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• 2000

Objective : Hedyotis diffusa has been used as an anticancer agent for several decades in oriental medicine. We test whether the methanol extract of the herb affects transcriptional activation factors including $NF-{\kappa}B$ and AP-1. Methods : 1. HL-60 cells were treated with various concentrations(from 200 to $50{\mu}g/ml$) of methanol extract and $H_2O$ extract($200{\mu}g/ml$)of hedyotis diffusa, After 48h later, the cells were tested for viability by MTT assay. 2. The HL-60 cells were treated with $200{\mu}g/ml$ of methanol extract for the indicated periods. First. Nuclear extracts were isolated and incubated with oligonucleotide probe of $NF-{\kappa}B$ and AP-1. Second. Nuclear extracts were isolated and reacted with p50, p65. c-rel pan-Jun, c-Jun, JunB. JunD antibody on ice for 30min. Finally The cell lysates were prepared and analyzed by western blotting using anti-Fas, anti-FasL and anti-p53 antibody. Results : 1. The methanol extract decreases the viability of human lymphoid origin leukemia HL-60 cells in a dose-dependent manner. 2. $NF-{\kappa}B$ is rapidly activated by the addition of the methanol extract, reaches a peak at 30min and gradually returns to resting level. We confirm that $NF-{\kappa}B$ is a heterodimer mainly composed of p65 subunit with c-Rel. 3. Transcriptional activation of AP-1 is detected at 30min and reaches a maximum at 1hr after stimulation of the cells with the methanol extract. AP-1 is mainly composed with Jur-D and partially Jug-B proteins. 4. the methanol extract of Hedyotis diffusa induces the expression of Fas, Fas ligand and p53 proteins of HL-60 cells in a time dependent fashion. Conclusions : These results suggest that the methanol extract of Hedyotis diffusa exerts anticancer effects to induce the death of human leukomic HL-60 cells via activation of trascriptional factors such as $NF-{\kappa}B$ and AP-1, increase in expression of Fas mediated signalling proteins, and induction of tumor suppressor gene. p53.

• Journal of Ginseng Research
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• 제23권4호
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• pp.235-238
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• 1999

[ $K_{ATP}$ ]채널은 세포내 ATP에 의해서 억제되는 포타슘 채널로서 혈관평활근, 골격근 및 체장의 ${\beta}$세포 막에 존재하여, 근세포의 막전압 조절을 통하여 근수축 및 이완을 조절할 뿐만 아니라 췌장의 ${\beta}$세포로부터 인슐린분비를 조절한다. 홍삼 복합사포닌 및 사포닌 $Rg_3$ 성분은 토끼 관상동맥 평활근세포의 칼슘의존성-포타슘채널$(BK_{Ca})$의 활성을 증가시켜 막전압의 과분극을 유발하여 혈관평활근을 이완시킨다. 사포닌 $Rg_3$성분은 홍삼의 복합사포닌 성분보다 $BK_{Ca}$에 더 높은 활성을 보이기 때문에 본 연구는 사포닌 $Rg_3$성분이 토끼 관상동맥 단일 평활근세포의 ${\beta}$채널의 활성도를 조절하는지를 팻치클램프 방법으로 기록하였다. 막전압 의존성과 함께 내향전류(inward rectification)특성을 보이는 ${\beta}$채널의 활성을 토끼 관상동맥 평활근 세포로부터 기록하였다. 이 ${\beta}$채널은 ATP와 giyburide에 의해서 억제되었으며 minoxidil에 의해서 활성이 증가되었다. 홍삼 사포닌 $Rg_3$성분은 $K_{ATP}$채널의 전류극대치에는 영향을 주지 않고 전류의 inactivation을 억제시켜 결과적으로 $K_{ATP}$채널의 활성을 증가시켰으며, 단일 KhTr채널이 열리는 시간도 증가시켰다. 따라서 본 실험 결과는 사포닌 $Rg_3$성분이 KATP채널의 활성을 증가시켜 막전압을 조절하여 관상동맥 평활근의 이완을 촉진한다고 여겨진다.

• International Journal of Stem Cells
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• 제16권4호
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• pp.425-437
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• 2023

Obesity, which continues to increase worldwide, was shown to irreversibly impair the differentiation potential and angiogenic properties of adipose tissue mesenchymal stromal cells (ADSCs). Because these cells are intended for regenerative medicine, especially for the treatment of inflammatory conditions, and the effects of obesity on the immunomodulatory properties of ADSCs are not yet clear, here we investigated how ADSCs isolated from former obese subjects (Ex-Ob) would influence macrophage differentiation and polarization, since these cells are the main instructors of inflammatory responses. Analysis of the subcutaneous adipose tissue (SAT) of overweight (OW) and Ex-Ob subjects showed the maintenance of approximately twice as many macrophages in Ex-Ob SAT, contained within the CD68⁺/FXIII-A^- inflammatory pool. Despite it, in vitro, coculture experiments revealed that Ex-Ob ADSCs instructed monocyte differentiation into a M2-like profile, and under inflammatory conditions induced by LPS treatment, inhibited HLA-DR upregulation by resting M0 macrophages, originated a similar percentage of TNF-α⁺ cells, and inhibited IL-10 secretion, similar to OW-ADSCs and BMSCs, which were used for comparison, as these are the main alternative cell types available for therapeutic purposes. Our results showed that Ex-Ob ADSCs mirrored OW-ADSCs in macrophage education, favoring the M2 immunophenotype and a mixed (M1/M2) secretory response. These results have translational potential, since they provide evidence that ADSCs from both Ex-Ob and OW subjects can be used in regenerative medicine in eligible therapies. Further in vivo studies will be fundamental to validate these observations.

• 대한소아치과학회지
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• 제26권2호
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• pp.218-231
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• 1999

마취된 흰쥐를 사용하여 해마의 CA영역에 위치한 피라밋세포들의 세포막 특성을 in vivo의 세포내 기록법에 의해서 관찰한 후 2.5% neurobiotin을 세포내 기록용 미세전극에 채워 세포내로 충진시킨후 충진전과 동일한 실험순서로 반응을 다시 관찰하고 ABC kit를 이용하여 면역조직염색을 행하여 형태학적인 관찰을 하였다. 피라밋세포의 세포내 반응 특성은 높은 휴지막 세포막전위, 낮은 input resistance 그리고 큰 활동전위를 가졌다. neurobiotin 충진 전 후에 따른 세포막 특성의 변화는 sustained AHP의 duration과 amplitude, input resistance, 그리고 세포외 및 세포내 자극에 따른 AP 수에서 유의한 차이를 보였고(P<0.05), 세포외 자극에 의한 억제는 주로 전반부에 나타났으며 CA3 영역에 위치한 이 세포의 형태학적 관찰 결과 세포체는 피라밋층에서 분명한 피라미드 형태를 띄고 있었고 기저 및 선단 가지가 각각 백색판층 및 섬유방-분자층까지 뻗어 있었으며 축삭은 겉질을 향해 기저가지돌기면에서 수직으로 뻗어 있었다. 해마의 주세포인 피라밋세포의 세포막 특성과 세포내 염색지시체(marker)로 주로 쓰이는 neurobiotin에 의해 세포막 특성중 일부가 변화됨을 알 수 있었고, 뇌내의 신경세포연결망이 완전히 보존되어 세포들 사이의 시냅스관계를 추측할 수 있는 in vivo 실험 모델이 응용될 수 있음을 제시하였다.