• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.88-88
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• 1995

Tetrahydroisoquinoline (THI) compounds have various pharmacological actions in the cardiovascular system. Recently, we have synthesized 1-${\alpha}$-naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, YS 49. In the present study, we evaluated the effect of YS-49 on positive inotropic and chronotropic action using isolated rat heart and on blood pressure and heart rate using anesthesized rabbit. Vasodilating action was also assessed in isolated rat thoracic aorta. YS 49, concentration-dependently relaxed rat aorta precontracted with phenylephrine (PE, 0.3 ${\mu}$M) and high potassium (high K$\^$+/, 65.4 mM). The 50% inhibitory concentration (IC$\sub$50/) of YS 49 in PE-induced and high K$\^$+/-induded contraction was 5.36 ${\mu}$M and 2.52 ${\mu}$M, respectively. In isolated rat atria, YS 49 increased both heart rate and force, and in anesthesized rabbit it decreased blood pressure but increased heart rate. In addition, to know the mechanism of action of the compound, propranolol, nonselective ${\beta}$-antagonist, and phentolamine, ${\alpha}$-blocker, were used. Furthermore, a comparison with the effect of higenamine, trimetoquinol on the vasodilating action in rat thoracic aorta was also made. The action of YS 49 was inhibited by the presence of propranolo, not pentolamine. These results indicate that cardiotonic and vasodilatory action of YS 49 is attributable, at least in part, for ${\beta}$-receptor stimulation.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1084-1088
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• 1995

A complete solid solution (SrLaAl1-xNixO4) between insulating SrLaAlO4 and metallic SrLaNi(Ⅲ)O4 oxides were prepared under high oxygen pressure (1.5 kbar, 800 ℃). They have tetragonal K2NiF4-type structure in all the solid solution range. Compared with lattice parameters of the same solid solution prepared under normal condition (1 bar, 1200 ℃), large decrease in the c-parameter was induced by high pressure treatment while no noticeable variation of the a-parameter was observed. Although marked changes of structural parameters, magnetic susceptibilities, and electron paramagnetic resonance spectra were consistently occurred before and after x=0.5, overall behaviors were essentially the same with those of solid solution prepared under normal condition. Such a phenomenon is explained by assuming the formation of partially filled narrow σ*x2-y2 band for x>0.5. Lattice contraction along the c-axis by high pressure treatment seems not to broaden this band. Particularly, the continuous absorption characteristic of a high free carrier concentration for x>0.5 and the absence of Ni-O in-plane stretching mode in the infrared absorption spectra supports this picture. However, the conductivities increasing with temperature for all solid solution suggest that some localization character, of probably Anderson type, remains for x>0.5.

• YAKHAK HOEJI
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• v.59 no.4
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• pp.158-163
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• 2015

Cardiac myocytes are subjected to fluid shear stress during each contraction and relaxation. Under pathological conditions, such as valve disease, heart failure or hypertension, shear stress in cardiac chamber increases due to high blood volume and pressure. The shear stress induces proarrhythmic longitudinal global $Ca^{2+}$ waves in atrial myocytes. In the present study, we further explored underlying cellular mechanism for the shear stress-induced longitudinal global $Ca^{2+}$ wave in isolated rat atrial myocytes. A shear stress of ${\sim}16dyn/cm^2$ was applied onto entire single myocyte using pressurized fluid puffing. Confocal $Ca^{2+}$ imaging was performed to measure local and global $Ca^{2+}$ signals. Shear stress elicited longitudinally propagating global $Ca^{2+}$ wave (${\sim}80{\mu}m/s$). The occurrence of shear stress-induced atrial $Ca^{2+}$ wave was eliminated by the inhibition of ryanodine receptors (RyRs) or inositol 1,4,5-trisphosphate receptors ($IP_3Rs$). In addition, pretreatment of phospholipase C (PLC) inhibitor U73122, but not its inactive analogue U73343, abolished the generation of longitudinal $Ca^{2+}$ wave under shear stress. Our data suggest that shear-induced longitudinal $Ca^{2+}$ wave may be induced by $Ca^{2+}$-induced $Ca^{2+}$ release through the RyRs which is triggered by $PLC-IP_3R$ signaling in atrial myocytes.

• Archives of Pharmacal Research
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• v.14 no.2
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• pp.181-187
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• 1991

The muscarinic antagonist 1-[benzilic 4, 4'-$[^3H]$ QUINUCLIDINYL BENZILATE $([^3H]$ QNB) bound to a single class of muscarinic receptors with high affinity in rabbit ileal membranes. The $K_D\;and\;B_{ max}$ values for $([^3H]$ QNB calculated from analysis of saturation isotherms were 52.5 pM AND 154 fmol/mg, respectively. Chlopheniramine (CHP), histamine $H_1$ blocker, increased $K_D$ vlue for $([^3H]$QNB without affecting the binding site concentrations and Hill coefficient. The $K_i$ value of CHP for inhibition of $([^3H]$QNB binding in ileal membranes was 1.44\mu{M}$ and the pseudo-Hill coefficient for CHP was close to unit. In the functional assay carbachol, muscarinic agonist, increased the contractile force of ileum with $ED_{50}$ value of $0.11\mu{M}$. CHP caused the rightward shift of the dose-response curve to carbachol. The $pA_2$ value of CHP determined from Schild analysis of carbacholinduced contraction was 5.77 and the slope was unity indicating competitive antagonism with carbachol. The dissociation constant $(K_i)$ of CHP obtained in competitive experiments with $([^3H]$ QNB was similar to the $K_A$ value (1.69 \mu{M)}$ of CHP as inhibitor of carbachol induced contraction in rabbit ileum. This result suggest that the binding of $H_i$ blocker. CHP, vs $([^3H]$QNB to muscarinic receptors in ileal membranes represents an interaction with a receptor of physiological relevance.

• Journal of Yeungnam Medical Science
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• v.11 no.1
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• pp.186-192
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• 1994

Amiodarone has a potent suppressive effect on supraventricular and ventricular dysrhythmias, so has widely used as a class III antiarrhythmic agent. However, significant side effects were noted in over 50% of patients treated. Pulmonary toxicity represents the most serious adverse raeaction limiting the clinical efficacy of this new antidysrhythmic drug. A 66-year-old male had received amiodarone 200mg/day for 7 months to control high grade ventricular premature contraction and was admitted due to dyspnea on exertion for 1 week. At the time of admission end-inspiratory crepitant rale was heard on auscultation. The roentgenogram of his chest revealed reticular and granular radioopaque densities on both lower lung fields and high resonance CT revealed interstitial fibrosis and pneumonic consolidations on the periphery of the both middle and lower lobes. Trans-bronchoscopic lung biopsy revealed nonspecific intersitial fibrosis. The laboratory findings were non-specific. We present a case of amiodarone-induced interstitial pulmonary disease clinically improved by cortico-steroid therapy.

• Journal of Environmental Science International
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• v.25 no.6
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• pp.853-864
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• 2016

Meteo-tsunamis are tsunamis that are typically caused by strong atmospheric instability (e.g., pressure jumps) in low pressure systems, but some meteo-tsunamis in winter can be caused by local atmospheric instability in high pressure systems (e.g., the Siberian High). In this study, we investigated a meteo-tsunami event related to a high pressure system that occurred during winter on the Yellow Sea in 2005. Sea level data from tidal stations were analyed with a high-pass filter, and we also performed synoptic weather analyses by using various synoptic weather data (e.g., surface weather charts) collected during the winter season(DJF) of 2005. A numerical weather model (WRF) was used to analyze the atmospheric instability on the day of the selected event (21 Dec. 2005). On the basis of the results, we suggest that the meteo-tsunami triggered by the high pressure system occurred because of dynamic atmospheric instability induced by the expansion and contraction of the Siberian High.

• The Korean Journal of Pharmacology
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• v.24 no.1
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• pp.103-109
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• 1988

Cyclobuxine D, extracted from Buxus microphylla var. koreana Nakai, is a steroidal alkaloid. Many pharmacological effects of cyclobuxine D were examined in our Lab. Cyclobuxine D showed a significant bradycardic effect in the rat heart and an inhibitory action on acetylcholine and $Ba^{++}-induced$ contraction of the longitudinal muscle isolated from the rabbit jejunum. In this study, we investigated the effect of cyclobuxine D on the contractile response-elicited by acetylcholine, oxytocin and $Ba^{++}$ in rat uterine. In order to analyse the inhibitory action of cyclobuxine D on the smooth muscle, we examined the inhibitory action of cyclobuxine D against the contractile response of the high potassium-depolarized rat ileum to calcium. Concentration-dependent decrease in the peak tension and duration of the acetylcholine, oxytocin and $Ba^{++}-induced$ contraction in the isolated rat uterus was observed when cyclobuxine D was added to the organ bath. The isolated longitudinal muscle from the rat ileum was immersed calcium-depleted potassium-depolarizing solution. Ten minutes after, 1.8 mM $CaCl_2$ was added to muscle bath and elicited a biphasic increase in muscle tension. Cyclobuxine D $(6.2{\times}10^{-5}\;M)$ produced an appreciable inhibition of both components of the mechanical response. In addition, $3.1{\times}10^{-4}\;M$ cyclobuxine D, introduced at a point when the tonic response had reached its maximum level, caused the muscle to exhibit a rapid lose of tension. Based on these experimental results, we propose the possibility that the inhibitory action of cyclobuxine D on the acetylcholine, oxytocin and $Ba^{++}-induced$ contraction in the isolated rat uterus may be due to blocking potassium-activated calcium channels, voltage-sensitive calcium channels.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.149-157
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• 1994

The role of nitric oxide(NO) as neurotransmitter in non-adrenergic non-cholinergic (NANC) relaxation induced by electrical stimulation has been studied in circular muscle strips of the rabbit gastric fundus. In the presence of atropine and guanethidine, low frequency$(1{\sim}20\;Hz)$ and short trains (5s) of electrical stimulation induced the frequency-dependent relaxations which were not affected by adrenergic and cholinergic blockage, but abolished by tetrodotoxin, a nerve conductance blocker. L-NNA, a stereospecific inhibitor of NO biosynthesis, inhibited the relaxations induced by electrical stimulation but not affected the relaxation to exogenous NO. The effect of L-NNA was prevented by L-arginine, the precursor of the NO biosynthesis, but not by its enantiomer, D-arginine. Exogenous administration of NO$(10{\sim}100\;{\mu}M)$ caused the concentration-dependent relaxation which showed a similarity to those obtained with electrical stimulation. Hemoglobin, a NO scavenger, abolished the NO-induced relaxations and also markedly inhibited those evoked by electrical stimulation. Application of adenosine triphosphate$(1{\sim}10\;{\mu}M)$ induced concentration-independent contractions, but in high dose caused temporary contraction followed by relaxation which was not affected by L-NNA. Exogenous vasoactive intestinal polypeptide$(10{\sim}100\;nM)$ induced the concentration-dependent relaxation, while its effects were slower in onset and more persistent than those induced by short trains and low frequencies of electrical stimulation. Based on above results, it is suggested that NO is the principal neurotransmitter of NANC nerve at relaxation induced by short trains and low frequencies of electrical stimulation in the rabbit gastric fundus.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.1
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• pp.1-11
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• 2000

We propose a predistorter to compensate for nolinear distortion induced by a high power amplifier employed in multi carrier-code division multiple access (MC-CDMA) systems. The proposed scheme rests upon the fixed point iteration (FPI) associated with the contraction mapping theorem. Unlike the predistorter based on the FPI already presented by the authors in other literatures which operates on complex-valued modulation signals, the proposed predistorter in this paper deals with real-valued FPI on modulation signal amplitudes, resulting in less complexity. Simulation results on a BPSK-modulated, 64-subcarrier synchronous MC-CDMA baseband system with a traveling wave tube amplifier in the transmitter, indicate that the proposed predistorter achieves significant improvement in terms of bit error rate and total degradation over those without the predistorter. Moreover, the proposed predistorter outperforms the complex-valued counterpart, in particular, for small output back-off levels.

• Biomolecules & Therapeutics
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• v.5 no.4
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• pp.369-375
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• 1997

General pharmacological effects of SB-31$^{R}$, the extracts of Pulsatilla koreana, were investigated in mice, rats and guinea-pigs. Intravenous injection of SB-31 (3 and 6 ml/kg) produced almost no effect on central nervous system no effects on the general symptom and behaviors of mice, spontaneous locomotor activity, pentobarbital- induced sleeping time , rotared performance , electroshock and pentylenetertrazole -induced seizures, acetic acid-induced writhing and normal body temperature in mice. SB-31 showed little effects on the spontaneous movement of the isolated ileum and contraction induced by agonists in isolated ileum, suggesting no influence on autonomic nervous system. Administration of SB-31 also did not show any effect on blood pressure in conscious rats. However, a slight decrease in heart rate was observed at high doses (6 and 10 ml/kg) of SB-31 in conscious rats. Similarly, a slight increase in respiratory rate was observed at 6 m1/kg of SB-31 in anesthetized rats. SB-31 did not produce any effect at the dose of 3 ml/kg, but showed a tendency to increase the urinary volume at 6 ml/kg, and produced a decrease in urinary excretions of N $a_{+}$and $K_{+}$at 6 ml/kg. However, transport capacity within the gastrointestinal tract and the secretion of the gastric juice were not influenced by 6 ml/kg of SB-31. In conclusion, these results suggest that SB-31 did not pro-duce any acute effects on the central nervous system, autonomic nervous system, respiratory and circulatory systems, digestive system and kidney function at the dose of below 3 ml/kg.ml/kg.