• Title/Summary/Keyword: duration of action

Search Result 298, Processing Time 0.027 seconds

Lithspermic acid-A slows down the inactivation kinetics of cardiac $Na^+$ current by intracellular $Ca^{2+}$-dependent mechanisms

  • Yoon, Jin-Young;Hyuncheol Oh;Ho, Won-Kyung;Lee, Suk-Ho
    • Proceedings of the Korean Biophysical Society Conference
    • /
    • 2003.06a
    • /
    • pp.46-46
    • /
    • 2003
  • Salviae Miltiorrhizae Radix has been used for treatment of cardiovascular diseases in oriental medicine. To investigate the possible involvement of cardiac ion channel in this effect, we examined electrophysiological effects of the extract of Salviae Miltiorrhizae Radix on action potentials and ionic currents in rat ventricular myocytes. The extracts of Salviae Miltiorrhizae Radix were fractionated into nine fractions, and the effect of each fraction on action potential was tested. The fraction containing monomethyl lithospermic acid-A (LSA-A) induced a significant prolongation of action potential duration (APD). LSA-B which is a major component of Salviae Miltiorrhizae Radix, however, did not cause a significant effect. In voltage clamp experiments, the effects of LSA-A on K currents, Ca currents and Na currents were tested. Neither K currents nor L-type Ca currents were affected by LSA-A. On the contrary, LSA-A significantly slowed down the inactivation kinetics of the Na current with no effect on the fast component of the inactivation process. The amplitude of the peak current and the voltage-dependence of activation were not changed by LSA-A. The effect of LSA-A on Na current was abolished when high concentration of $Ca^{2+}$ buffer (10 mM BAPTA) was included in the pipette solution or when Ca2+ current was blocked by nicardipine (1 $\mu$M) in the bath solution.n.

  • PDF

Effects of Paroxetine on a Human Ether-a-go-go-related Gene (hERG) K+ Channel Expressed in Xenopus Oocytes and on Cardiac Action Potential

  • Hong, Hee-Kyung;Hwang, Soobeen;Jo, Su-Hyun
    • International Journal of Oral Biology
    • /
    • v.43 no.1
    • /
    • pp.43-51
    • /
    • 2018
  • $K^+$ channels are key components of the primary and secondary basolateral $Cl^-$ pump systems, which are important for secretion from the salivary glands. Paroxetine is a selective serotonin reuptake inhibitor (SSRI) for psychiatric disorders that can induce QT prolongation, which may lead to torsades de pointes. We studied the effects of paroxetine on a human $K^+$ channel, human ether-a-go-go-related gene (hERG), expressed in Xenopus oocytes and on action potential in guinea pig ventricular myocytes. The hERG encodes the pore-forming subunits of the rapidly-activating delayed rectifier $K^+$ channel ($I_{Kr}$) in the heart. Mutations in hERG reduce $I_{Kr}$ and cause type 2 long QT syndrome (LQT2), a disorder that predisposes individuals to life-threatening arrhythmias. Paroxetine induced concentration-dependent decreases in the current amplitude at the end of the voltage steps and hERG tail currents. The inhibition was concentration-dependent and time-dependent, but voltage-independent during each voltage pulse. In guinea pig ventricular myocytes held at $36^{\circ}C$, treatment with $0.4{\mu}M$ paroxetine for 5 min decreased the action potential duration at 90% of repolarization ($APD_{90}$) by 4.3%. Our results suggest that paroxetine is a blocker of the hERG channels, providing a molecular mechanism for the arrhythmogenic side effects of clinical administration of paroxetine.

Effects of Ginsenosides Injected Intrathecally or Intracerebroventricularly on Antinociception Induced by D-$Pen^{2,5}$-enkephalin Administered Intracerebroventricularly in the Mouse

  • Hong-Won Suh;Don
    • Journal of Ginseng Research
    • /
    • v.21 no.2
    • /
    • pp.109-114
    • /
    • 1997
  • The effect of total saponin fraction of Ginseng injected intrathecally (i.1.) or in- tracerebroventricularly (i.c.v.) on the antinociception induced by D-$Pen^{2,5}$- enkephalin (DPDPE) ad ministered i.c.v. was studied in ICR mice in the present study. The antinociception was assessed by the tail-flick test. Total saponin fraction at doses 0.1 to 1.0 $\mu\textrm{g}$, which administered i.t. Alone did not affect the latencies of tail-flick threshold, attenuated dose-dependently the inhibition of the tail-flick response induced by i.c.v. administered DPDPE (10 $\mu\textrm{g}$). However, total saponin fraction at doses 1 to 20 $\mu\textrm{g}$, which administered i.c.v. Alone did not affect the latencies of the tail-flick response, did not affect i.c.v. administered DPDPE (10 $\mu\textrm{g}$)-induced antinociception. The duration of antagonistic action of total saponin fraction against DPDPE-induced antlnociception was lasted at least for 6 hrs. Various doses of ginsenosides Rd, but not $\Rb_2$, Rc, Rg1, and $\Rb_1$ and Re, injected i.t. Dose-dependently attenuated antinociception induced by DPDPE administered i.c.v. Our results indicate that total saponin fraction injected spinally appears to have antagonistic action against the antinociception induced by supraspinally applied DPDPE. Ginsenoside Rd appears to be responsible for blocking j.c.v. administered DPDPE-induced antinociception. On the other hand, total ginseng fraction, at supraspinal sites, may not have an antagonistic action against the antinociception induced by DPDPE.

  • PDF

Studies on the Efficacy of Combined Preparation of Crude Drugs (XXVII) -Experimental studies on the efficacy of Chunghyulgangki-Tang- (생약(生藥) 복합(複合) 제제(製劑)의 약효(藥效) 연구(硏究)제27보(第27報) -청혈강기탕(淸血降氣湯)의 약효(藥效)에 관한 실험적(實驗的) 연구(硏究)-)

  • Song, Il-Byung;Hong, Nam-Doo;Kim, Nam-Jae;Ko, Byoung-Hee
    • Korean Journal of Pharmacognosy
    • /
    • v.17 no.2
    • /
    • pp.113-122
    • /
    • 1986
  • In order to investigate the pharmacological activities of the combined preparation of crude drugs, Chunghyulgangki-Tang was studied. Chunghyulgangki-Tang has been widely used to cerebral apoploxy, hypertension and arteriosclerosis, etc. In this study, water extract of Chunghyulgangki-Tang was conducted in attempt to investigate for analgesic, sedative, antipyretic, isolated ileum and heart, blood vessels and blood pressure action in mice, frogs, rats, guinea-pigs and rabbits. The following results were obtained; Analgesic action by the acetic acid stimulating method in mice was recognized. Sedative activities by the wheel cage method and rotor rod method in mice were shown. Prolonged action against the hypnotic duration induced by thiopental-Na was significantly noted in mice. The effect of antipyretic in endotoxin febrile rats was significantly recognized. Spontaneous motility of the isolated ilem of mice was suppressed and contractions of the isolated ileum of mice and guinea-pigs induced by acetylcholine chloride, barium chloride and histamine were remarkably inhibited. Acceleration of isolated heart motility was shown in frogs. Vaso-dilating and hypotensive actions were recognized in rabbits. According to the above results, effects based on the oriental medicinal references were approximate to the actural experimental results.

  • PDF

Numerical Investigation into Behavior of Retaining Wall Subject to Cycles of Freezing and Thawing (동결-융해 반복작용에 노출되는 옹벽의 거동에 관한 수치해석 연구)

  • Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
    • /
    • v.29 no.1
    • /
    • pp.81-92
    • /
    • 2013
  • This paper presents the results of a numerical investigation into the behavior of retaining wall subject to cycles of freezing and thawing due to seasonal temperature change. The thermo-hydro-mechanical coupled finite element modeling strategy was first established to simulate the wall behavior. A series of finite element analyses were then performed on a range of conditions representing seasonal temperature change characteristics. The results indicated that the average freezing temperature and the number of cycles of freezing and thawing were the primary influencing factors for the wall behavior. Also revealed was that the duration of freezing period does not significantly affect the wall displacement and the lateral earth pressure, and that the earth pressure on the wall does not significantly change due to the freezing and thawing action suggesting that the increase in the wall displacement during the freezing and thawing action may be attributed to degradation of backfill due to the freezing and thawing action.

The Study on the Composition of Yongdamsagan-tang(龍膽瀉肝湯)'s Essential Oil Obtained by Supercritical Carbon Dioxide Extraction (초임계 유체 추출법을 이용한 용담사간탕(龍膽瀉肝湯) 약침액(藥鍼液)의 정유(精油)성분에 대한 연구(硏究))

  • Lee, Jae-Eun;Kim, Byeong-U;Im, Tae-Jin;Kim, Dong-Hui;Shin, Min-Seop;Yook, Tae-Han;Gwon, Gi-Rok
    • Journal of Pharmacopuncture
    • /
    • v.11 no.1
    • /
    • pp.177-187
    • /
    • 2008
  • Objectives : This study was performed to analyze the effective components of essential oil obtained from Yongdamsagantang, which has been efficacious against leukorrhea in gynecologic diseases. Methods : I obtained the essential oils of Yongdamsagan-tang by hydrodistillation extraction method and supercritical fluid extraction(SFE) method, and then I analyzed those by GC/MS(Gas Chromatography/Mass Spectrum). Results : 1. The optimum SFE(Supercritical Fluid Extraction) condition was obtained in the following experiment conditions: pressure 200atm, temperature $45^{\circ}C$, duration of extraction 25minutes. 2. With GC(Gas Chromatography) and GC/MS(Gas Chromato- graphy/Mass Spectrum) analysis, I identified 37 compounds in the Yongdamsagan-tang's essential oil obtained through the SFE method. The main compounds were as follows : 3-Methyl-but-2-enoic acid,2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H -pyrano[3,2-g]chromen-3-yl ester(49.81%), (Z)-6-Pentadecen-1 -ol(3.19%), (-)-Spathulenol(2.40%). 3. I identified 4 compounds in the Yongdamsagan-tang's essential oil obtained through the hydrodistillation method. The main compounds were as follows : 3-Methyl-but-2-enoic acid, 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano [3,2-g]chromen-3-yl ester(2.61%). 4. 3-Methy I-but-2-enoic acid, 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano[3,2-g] chromen-3-yl ester, all were identified in both the SFE method and the hydrodistillation method, but the others were not identified in common. 5. I also conducted an additional test in order to examine the essential oil's antimicrobial action against bacteria. Both MIC(Minimum Inhibitory Concentrations) and MBC(Minimum Bactericidal Concentrations) were $0.125mg/m{\ell}$ against N. meningitidis, however MIC and MBC were $1.0mg/m{\ell}$ in antimicrobial action against 12 different genera of bacteria.

Comparative Analysis of Open- Spike between Excellent and Non-excellent Players in Volleyball (배구 우수선수와 비우수선수간의 오픈 스파이크 동작의 비교 분석)

  • Kim, Chang-Bum;Kim, Young-Suk;Shin, Jun-Yong
    • Korean Journal of Applied Biomechanics
    • /
    • v.13 no.3
    • /
    • pp.253-264
    • /
    • 2003
  • This study aims at finding the structure of spike technique by analysing comparatively the spike action by excellent and by non-excellent players throughout the section from a flying jump to the time of landing for the correct analysis of spike action and tries to help athletes and coaches to execute a scientific training. For the objected person of this study, six of H College athletes three of excellent athletes and three of non-excellent athletes, presently registered as athlete with the Korea Volleyball federation) were chosen, and the factors of analysis were analysed upon performance time of action by section, human body centered displacement, change of articulation angle, speed change of articulation of the upper limbs, uniformity of the articulation of the upper limbs upon impact, etc. The conclusion of this study is as follow: 1. In the time required for taking action, it shows to take $1.067{\pm}0.057$ seconds for the group of excellent athletes and $1.034{\pm}0.033$ seconds for the group of non-excellent athletes. Although there was not big difference between two groups in the performance time of action, it showed that the group of excellent athletes takes longer compared to the group of non-excellent athletes. And it was found by the result of this study that the group of excellent athletes stays longer in the duration of flight. 2. In the displacements of horizontal movement and vertical movement, it was found that the group of excellent athletes have moved more than the group of non-excellent athletes in the horizontal movement of the center of human body 3. In the angles of wrist and knee, it was found that the excellent athletes have shown little than the non-excellent athletes in the entire sections, but that in the angle of elbow, the non-excellent athletes have shown bigger than the excellent athletes.. 4. In the speed of the articulation of the upper limbs upon impact, it was found that the group of excellent athletes have shown bigger than the group of non-excellent athletes, and that in the maximum value of the articulation of the upper limbs, the maximum value for the hand was indicated upon impact and that forearm and upper arm have shown the maximum value just before the impact. 5. In the uniformity of articulation of the upper limbs at the time of impact, the group of excellent athletes showed bigger than the group of non-excellent athletes in all the articulations.

Studies on the Fermentation of Fish Protein -1. A Model Design of Fermentor- (수산 발효식품 제조에 관한 연구 -1. 어육 발효조의 설계-)

  • Lee, Kang-Ho;Choi, Ho-Yeon
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.1 no.1
    • /
    • pp.51-62
    • /
    • 1972
  • In Korea, fermented fish has been playing an important role as a preserved and flavor rich food. It is said that the digestion of fish protein is due to both action of intrinsic (autolytic enzymes) and bacterial enzymes in fish. The mass production of fermented fish has been impeded since traditional method of fermentation requires a long duration for a complete digestion. A high concentration of salt and unsanitary condition are also considered disadvantages of the old method. To improve the quality of the product and to develop mechanized process of fermentation, fermentors which have such control device as temperature, pH and agitation control system have been urgently needed. In this study, a model design of a fermentor is studied. The calculation was based on the optimum conditions for enzymatic hydrolysis of fish protein which involve temperature, pH, viscosity and other factors.

  • PDF

Effect of Panax ginseng on Sleeping Time of Chicken Anesthetized with Pentobarbital Sodium (인삼분말(人蔘粉末)이 Pentobarbital Sodium으로 마취(麻醉)된 병아리의 수면시간(睡眠時間)에 미치는 영향(影響))

  • Park, Joon Hyoung;Ha, Sung Jin;Kim, Hwa Sik
    • Korean Journal of Veterinary Research
    • /
    • v.14 no.1
    • /
    • pp.41-44
    • /
    • 1974
  • The effect of Panax ginseng on the sleeping time of chicken anesthetized with pentobarbital sodium were observed to elucidate the influence of ginseng on the duration of action of barbiturates. The results were as follows: 1. By the oral administration of ginseng powder(0.1~0.6 g/day/head for a week) shortened the sleeping time of very young chicken anesthetized with pentobarbital sodium.

  • PDF

Evaluation of Bioavailability of Bioadhesive Microcapsules Containing Cephalexin (세팔렉신 함유 생체막점착성 마이크로캅셀의 생체이용율 평가)

  • Han, Kun;Kim, Jung-Hwan;Chung, Youn-Bok;Jee, Ung-Kil
    • Journal of Pharmaceutical Investigation
    • /
    • v.24 no.3
    • /
    • pp.177-186
    • /
    • 1994
  • Bioadhesive microcapsules of cephalexin, using Eudragit RS/RL coated with polycarbophil or carbopol, were evaluated biopharmaceutically. The GI transit of microcapsules in rats was studied. Bioadhesive microcapsules coated with polycarbophil or carbopol were shown to have substantially longer GI transit time than Eudragit RS/RL microcapsule. The delay in transit time was due to bioadhesion of the polymer to the mucin-epithelial cell surface which was clearly observable on animal autopsy. Plasma drug levels in rabbits showed that bioadhesive microcapsules resulted in a longer duration of action and greater bioavailability than other microcapsule or drug powder. Thus, the principle of bioadhesion can significantly improve therapy, due to a reduced rate of gastric emptying, an increase in contact time, and the intimacy of contact of the drug with the absorbing membrane.

  • PDF