• Integrative Medicine Research
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• 제6권2호
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• pp.149-155
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• 2017

Background: Naringenin (NRG) is a common dietary polyphenolic constituent of fruits. NRG has diverse pharmacological activities, and is used in traditional medicine to treat various diseases including gastrointestinal (GI) disorders. Interstitial cells of Cajal (ICCs) are pacemaker cells of the GI tract. In this study, the authors investigated the effects of NRG on ICCs and on GI motility in vitro and in vivo. Methods: ICCs were dissociated from mouse small intestines by enzymatic digestion. The whole-cell patch clamp configuration was used to record pacemaker potentials in cultured ICC clusters. The effects of NRG on GI motility were investigated by calculating percent intestinal transit rates (ITR) using Evans blue in normal mice. Results: NRG inhibited ICC pacemaker potentials in a dose-dependent manner. In the presence of tetraethylammonium chloride or iberiotoxin, NRG had no effect on pacemaker potentials, but it continued to block pacemaker potentials in the presence of glibenclamide. Preincubation with SQ-22536 had no effect on pacemaker potentials or on their inhibition by NRG. However, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one blocked pacemaker potential inhibition by NRG. In addition, L-NG-nitroarginine methyl ester blocked pacemaker potential inhibition by NRG. Furthermore, NRG significantly suppressed murine ITR enhancement by neostigmine in vivo. Conclusion: This study shows NRG dose-dependently inhibits ICC pacemaker potentials via a cyclic guanosine monophosphate/nitric oxide-dependent pathway and $Ca^{2+}$-activated $K^+$ channels in vitro. In addition, NRG suppressed neostigmine enhancement of ITR in vivo.

• 대한수의학회지
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• 제45권4호
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• pp.485-493
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• 2005

We studied the effects of trazodone on arterial blood pressure in anesthesized guinea pigs, and on vascular responses in isolated thoracic aorta. Trazodone produced a concentration-dependent relaxation in phenylephrine-precontracted endothelium intact (+E) rings, but not in a KCl-precontracted aortic rings. These relaxant effects of trazodone on +E rings were significantly greater than those on denuded (-E) rings. The trazodone-induced relaxation was suppressed by glibenclamide and tetrabutylammonium, but not by N(G)-nitro-L-arginine (L-NNA), N(omega)-nitro-L-arginine methyl ester (L-NAME), methylene blue (MB), nifedipine, indomethacin, 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate (NCDC) and clotrimazole. In vivo, infusion of trazodone elicited a significant decrease in arterial blood pressure. Trazodone-induced blood pressure lowering was markedly inhibited by intravenous pretreatment of prazosin but not by pretreatment of saponin, L-NNA, L-NAME, MB, nifedipine, glibenclamide, clotrimazole and NCDC. In addition, trazodone produced an increase in twitch force of isolated papillary muscle and left ventricular pressure of perfused heart. These findings suggest that the endothelium-independent vasorelaxant effect of trazodone may be explained by activation of $Ca^{2+}$-activated and ATP-sensitive $K^+$ channels, and the hypotensive effect of trazodone is not associated with cardiac contraction.

• Bulletin of the Korean Chemical Society
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• 제29권3호
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• pp.609-614
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• 2008

A periodic mesoporous organosilica material was synthesized by microwave heating (PMO-M) using 1,2-bis(trimethoxysilyl)ethane as a precursor in a cationic surfactant solution, and textural properties were compared with those of the product produced by conventional convection heating (PMO-C). These synthesized materials were characterized using XRD, TEM/SEM, N2 adsorption isotherm, 29Si and 13C NMR, and TGA, which confirmed their good structural orders and clear arrangements of uniform 3D-channels. Synthesis time was reduced from 21 h in PMO-C to 2-4 h in PMO-M. PMO-M was made of spherical particles of 1.5-2.2 m m size, whereas PMO-C was made of decaoctahedron-shaped particles of ca. 8.0 m m size. Effect of synthesis temperature, time, and heating mode on the PMO particle morphology was examined. The particle size of PMO-M could be controlled by changing the heating rate by adjusting microwave power level. PMO-M demonstrated improved separation of selected organic compounds compared to PMO-C in a reversed phase HPLC experiment. Ti-grafted PMO-M also resulted in higher conversion in liquid phase cyclohexene epoxidation than by Ti-PMO-C.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.625-637
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• 1997

Calcium ions are implicated in a variety of physiological functions, including enzyme activity, membrane excitability, neurotransmitter release, and synaptic transmission, etc. Calcium antagonists have been known to be effective for the treatment of exertional angina and essential hypertension. Selective and nonselective voltage-dependent calcium channel blockers also have inhibitory action on the acute and tonic pain behaviors resulting from thermal stimulation, subcutaneous formalin injection and nerve injury. This study was undertaken to investigate the effects of iontophoretically applied $Ca^{++}$ and its antagonists on the responses of WDR (wide dynamic range) cells to sensory inputs. The responses of WDR cells to graded electrical stimulation of the afferent nerve and also to thermal stimulation of the receptive field were recorded before and after iontophoretical application of $Ca^{++}$, EGTA, $Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA, ${\omega}-conotoxin$ MVIIC and ${\omega}-agatoxin$ IVA. Also studied were the effects of a few calcium antagonists on the C-fiber responses of WDR cells sensitized by subcutaneous injection of mustard oil (10%). Calcium ions and calcium channel antagonists ($Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA & ${\omega}-agatoxin$ IVA) current-dependently suppressed the C-fiber responses of WDR cells without any significant effects on the A-fiber responses. But ${\omega}-conotoxin$ MVIIC did not have any inhibitory actions on the responses of WDR cell to A-fiber, C-fiber and thermal stimulation. Iontophoretically applied EGTA augmented the WDR cell responses to C-fiber and thermal stimulations while spinal application of EGTA for about $20{\sim}30\;min$ strongly inhibited the C-fiber responses. The augmenting and the inhibitory actions of EGTA were blocked by calcium ions. The WDR cell responses to thermal stimulation of the receptive field were reduced by iontophoretical application of $Ca^{++}$, verapamil, ${\omega}-agatoxin$ IVA, and ${\omega}-conotoxin$ GVIA but not by ${\omega}-conotoxin$ MVIIC. The responses of WDR cells to C-fiber stimulation were augmented after subcutaneous injection of mustard oil (10%, 0.15 ml) into the receptive field and these sensitized C-fiber responses were strongly suppressed by iontophoretically applied $Ca^{++}$, verapamil, ${\omega}-conotoxin$ GVIA and ${\omega}-agatoxin$ IVA. These experimental findings suggest that in the rat spinal cord, L-, N-, and P-type, but not Q-type, voltage-sensitive calcium channels are implicated in the calcium antagonist-induced inhibition of the normal and the sensitized responses of WDR cells to C-fiber and thermal stimulation, and that the suppressive effect of calcium and augmenting action of EGTA on WDR cell responses are due to changes in excitability of the cell.

• The Korean Journal of Physiology and Pharmacology
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• 제16권2호
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• pp.139-144
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• 2012

It has been reported that activation of metabotropic glutamate receptor 1 (mGluR1) can mediate endocannabinoid-induced short-term depression of synaptic transmission in cerebellar parallel fiber (PF)-Purkinje cell (PC) synapse. mGluR1 has signaling pathways involved in intracellular calcium increase which may contribute to endocannabinoid release. Two major mGluR1-evoked calcium signaling pathways are known: (1) slow-kinetic inward current carried by transient receptor potential canonical (TRPC) channel which is permeable to $Ca^{2+}$; (2) $IP_3$-induced calcium release from intracellular calcium store. However, it is unclear how much each calcium source contributes to endocannabinoid signaling. Here, we investigated whether calcium influx through mGluR1-evoked TRPC channel contributes to endocannabinoid signaling in cerebellar Purkinje cells. At first, we applied SKF96365 to inhibit TRPC, which blocked endocannabinoid-induced short-term depression completely. However, an alternative TRP channel inhibitor, BTP2 did not affect endocannabinoid-induced short-term depression although it blocked mGluR1-evoked TRPC currents. Endocannabinoid signaling occurred normally even though the TRPC current was mostly blocked by BTP2. Our data imply that TRPC current does not play an important role in endocannabinoid signaling. We also suggest precaution in applying SKF96365 to inhibit TRP channels and propose BTP2 as an alternative TRPC inhibitor.

• Restorative Dentistry and Endodontics
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• 제27권5호
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• pp.451-462
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• 2002

삼차신경은 구강악안면영역의 운동 및 감각을 담당하고 있으므로 치과임상에서 매우 중요하다. 삼차신경근 중 삼차신경절에 세포체를 갖는 뉴론은 주로 체성 감각을 전달하는 1차 구심신경으로 악안면영역의 촉각, 압각, 진동감각 온도각 및 통각을 담당한다. 이러한 감각의 전달은 기본적으로 신경세포의 이온통로의 활동에 의존하는데 삼차신경절 세포에 여러 종류의 이온통로가 존재하는 것으로 알려져 있다. 본 연구에서는 항체 염색법을 이용하여 이온통로가 존재를 확인 하고자 한다. 횐쥐의 삼차신경절로부터 통법에 따라 뉴론을 단일 세포로 분리하고 immunocytochemistry 방법으로 세포를 염색하여 관찰한 바 다음과 같은 결과를 얻었다. 본 실험에서 이온전류의 측정 등으로 관찰된 여러 종류의 이온통로들을 면역 염색법으로 확인하였다. 횐쥐의 삼차신경절 뉴론에서 확인된 이온통로는 소디움통로와 N, P 및 Q-type의 칼슘통로 그리고 BK$_{Ca}$, Kv 4.2 및 Kir 2.1 등의 포타슘통로이었으며 이온통로의 종류에 따라 분포에 차이를 나타내었다.

• 한국광물학회지
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• 제27권2호
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• pp.97-105
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• 2014

일월탄광에는 산화조, SAPS, 소택지의 3단계 자연정화시설이 설치되어 있으며 갱내수를 모아 정화한 후 주변 하천으로 유출시키고 있다. 일월탄광 갱내수의 pH 값은 계절에 관계없이 2.28-2.42로 낮은값을 나타내지만 산화조를 거치는 동안 pH 값은 6.17-6.53 급격하게 증가한다. 정화시설에 의한 정화효율은 $SO_4$, Mg, Al, Ca, Mn은 각각 약 50%, 40%, 100%, 24%, 59%이다. 갱내수의 Fe는 아주 낮은 값($1.06-1.09mg/{\ell}$)이지만 정화시설을 거치는 동안 100%의 제거효율을 나타낸다. 이와 같이 일월탄광에 설치한 정화시설은 pH 상승과 Fe와 Al의 제거 효율은 높지만 $SO_4$, Mg, Ca, Mn 등은 60% 이하로 상대적으로 낮다. 따라서 이러한 이온을 제거하기 위해서는 다른 정화기술을 적용해야 할 것으로 판단된다. pH 2.28-2.42 범위인 갱내수가 유입되는 정화시설 바닥에 침전되는 침전물은 슈워트마나이트이며 ($Fe_8O_8(OH)_6SO_4$), pH 5.83-5.96인 침출수에서는 2-line 페리하이드라이트(2-line $Fe_2O_3{cdot}0.5H_2O$H2O)가 침전된다.

• BMB Reports
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• 제33권3호
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• pp.202-207
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• 2000

The depletion of intracellular calcium stores by thapsigargin treatment evoked extracellular calcium-dependent membrane currents in Xenopus laevis oocytes. These currents have been compared to those evoked by microinjection of a calcium influx factor (CIF) purified from Jurkat T lymphocytes. The membrane currents elicited by thapsigargin treatment (peak current, $163{\pm}60$ nA) or CIF injection (peak current, $897{\pm}188$ nA) were both dependent on calcium entry, based on their eradication by the removal of extracellular calcium. The currents were, in both cases, attributed primarily to well-characterized $Ca^{2+}-dependent$ $Cl^-$ currents, based on their similar reversal potentials (-24 mV vs. -28 mV) and their inhibition by niflumic acid (a $Cl^-$ channel blocker). Currents induced by either thapsigargin treatment or CIF injection exhibited an identical pattern of inhibitory sensitivity to a panel of lanthanides, suggesting that thapsigargin treatment or CIF injection evoked $Cl^-$ currents by stimulating calcium influx through pharmacologically identical calcium channels. These results indicate that CIF acts on the same calcium entry pathway activated by the depletion of calcium stores and most lanthanides are novel pharmacological tools for the study of calcium entry in Xenopus oocytes.

• 한국지구과학회지
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• 제32권7호
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• pp.707-718
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• 2011

보성-화순지역 하상퇴적물에 대한 지질집단별 자연배경치와 지구화학적 특성에 대해 연구하였다. 이를 위해 1차 수계를 따라 하상퇴적물시료 186개를 채취하였고, 실험실에서 자연건조 시킨 후, XRF, ICP-AES, NAA분석을 실시하였다. 하상퇴적물의 지질집단별 자연배경치와 지구화학적 특성을 알기 위해, 시료를 화강암질편마암(GGn)지역과 반상변정질편마암(PGn)지역으로 분리하였다. 화강암질편마암지역의 주성분원소 함량은 $SiO_2$ 45.5-73.09 wt.%, $Al_2O_3$ 12-20.76 wt.%, $Fe_2O_3$(T) 3.72-8.85 wt.%, $K_2O$ 2.38-4.2 wt.%, MgO 0.75-2.77 wt.%, $Na_2O$ 0.78-1.88 wt.%, CaO 0.27-2.1 wt.%, $TiO_2$ 0.56-1.72 wt.%, $P_2O_5$ 0.06-0.73 wt.% and MnO 0.03-0.95 wt.%이고 반상변정질편마암지역의 주성분원소 함량은 $SiO_2$ 43.74-70.71 wt.%, $Al_2O_3$ 11.54-25.05 wt.%, $Fe_2O_3$(T) 3.44-13.46 wt.%, $K_2O$ 2.08-3.86 wt.%, MgO 0.65-2.99 wt.%, $Na_2O$ 0.63-1.7 wt.%, CaO 0.35-2.07 wt.%, $TiO_2$ 0.68-4.17wt.%, $P_2O_5$ 0.1-0.31 wt.% and MnO 0.07-0.33 wt.%이다. 화강암질편마암지역 하상퇴적물의 위해원소 함량은 크롬 41.7-242 ppm, 코발트 7.6-25.1 ppm, 니켈 12-61 ppm, 구리 10-47 ppm, 아연 48.5-412 ppm, 납 17-215 ppm이고 반상변정질편마암지역은 크롬 29.6-454 ppm, 코발트 5.9-53.7 ppm, 니켈 8.7-287 ppm, 구리 6.4-134 ppm, 아연 43.6-370 ppm, 납 15-37 ppm이다. 화강암질편마암지역에서 크롬은 MgO와 코발트는 $Al_2O_3$, $Fe_2O_3$(T), MgO와 니켈은 $Fe_2O_3$(T), CaO, MgO와 높은 상관성을 가지나, 구리, 아연, 납은 비교적 낮은 상관성을 보였다. 반상변정질편마암지역에서 일반적으로 크롬, 코발트, 니켈, 구리는 주성분원소와 대부분 높은 상관성을 보였으나, 아연과 납은 낮은 상관성을 보였다.

• The Korean Journal of Physiology and Pharmacology
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• 제22권3호
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• pp.311-319
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• 2018

Mitochondrial calcium overload is a crucial event in determining the fate of neuronal cell survival and death, implicated in pathogenesis of neurodegenerative diseases. One of the driving forces of calcium influx into mitochondria is mitochondria membrane potential (${\Delta}{\psi}_m$). Therefore, pharmacological manipulation of ${\Delta}{\psi}_m$ can be a promising strategy to prevent neuronal cell death against brain insults. Based on these issues, we investigated here whether nobiletin, a Citrus polymethoxylated flavone, prevents neurotoxic neuronal calcium overload and cell death via regulating basal ${\Delta}{\psi}_m$ against neuronal insult in primary cortical neurons and pure brain mitochondria isolated from rat cortices. Results demonstrated that nobiletin treatment significantly increased cell viability against glutamate toxicity ($100{\mu}M$, 20 min) in primary cortical neurons. Real-time imaging-based fluorometry data reveal that nobiletin evokes partial mitochondrial depolarization in these neurons. Nobiletin markedly attenuated mitochondrial calcium overload and reactive oxygen species (ROS) generation in glutamate ($100{\mu}M$)-stimulated cortical neurons and isolated pure mitochondria exposed to high concentration of $Ca^{2+}$ ($5{\mu}M$). Nobiletin-induced partial mitochondrial depolarization in intact neurons was confirmed in isolated brain mitochondria using a fluorescence microplate reader. Nobiletin effects on basal ${\Delta}{\psi}_m$ were completely abolished in $K^+-free$ medium on pure isolated mitochondria. Taken together, results demonstrate that $K^+$ influx into mitochondria is critically involved in partial mitochondrial depolarization-related neuroprotective effect of nobiletin. Nobiletin-induced mitochondrial $K^+$ influx is probably mediated, at least in part, by activation of mitochondrial $K^+$ channels. However, further detailed studies should be conducted to determine exact molecular targets of nobiletin in mitochondria.