• Title/Summary/Keyword: Action Potential

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Effects of Opioid Pure Agonists on the Excitibility of Frog Sciatic Nerve Fibers

  • Lee, Jong-Hwa;Frank, George-B.
    • Archives of Pharmacal Research
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    • v.16 no.2
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    • pp.83-88
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    • 1993
  • opioid pure agonists, morphine, meperidine and methadone, were used to investigate the effect on the opioid receptor of fron sciatic nerve fibers using sucrose gap apparatus. When applied extracellularly by perfusion, morphine, methadone and meperidine significantly depressed the amplitude of the action potential in frog sciatic nerve fibers as a dose-dependent $(10^{-10}\;M-10^{-2}\;M)$ manner. The depression with morphine or methadone was partially antagonized by the simultaueous treatment with a lower $(10^{-10}\;M-10^{-8}\;M)$ concentration of naloxone, but that of meperidine was not blocked. When the three opioid agonists were applied intracellularly by placing it in a compartment with a cut end of the sciatic nerve fibers, all of themn depressed the amplitude of the action potentials by similar potency, and these reductions significantly blocked by pretreatment of lower concentration $(10^{-10}\;M-10^{-8}M)$ of naloxone. These results support the previous findings by other workers that the stereospecific opioid receptors of this preparation are located on or near the intracellular opening of the sodium channels which are sensitive to naloxone.

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Anxiolytic Action of Taurine via Intranasal Administration in Mice

  • Jung, Jung Hwa;Kim, Sung-Jin
    • Biomolecules & Therapeutics
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    • v.27 no.5
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    • pp.450-456
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    • 2019
  • Taurine has a number of beneficial pharmacological actions in the brain such as anxiolytic and neuroprotective actions. We explored to test whether taurine could be transported to the central nervous system through the intranasal route. Following intranasal administration of taurine in mice, elevated plus maze test, activity cage test and rota rod test were carried out to verify taurine's effect on anxiety. For the characterization of potential mechanism of taurine's anti-anxiety action, mouse convulsion tests with strychnine, picrotoxin, yohimbine, and isoniazid were employed. A significant increase in the time spent in the open arms was observed when taurine was administered through the nasal route in the elevated plus maze test. In addition, vertical and horizontal activities of mice treated with taurine via intranasal route were considerably diminished. These results support the hypothesis that taurine can be transported to the brain through intranasal route, thereby inducing anti-anxiety activity. Taurine's anti-anxiety action may be mediated by the strychnine-sensitive glycine receptor as evidenced by the inhibition of strychnine-induced convulsion.

Modulatory action of enrofloxacin in lipopolysaccharide-induced hyper-activated mouse spleen cells (Lipopolysaccharide에 의해 과활성화된 마우스 비장세포에서 Enrofloxacin의 조절작용)

  • Ko, Hyeong-Ju;Joo, Hong-Gu
    • Korean Journal of Veterinary Research
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    • v.59 no.2
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    • pp.75-80
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    • 2019
  • Enrofloxacin, a fluoroquinolone, is a broad-spectrum antibiotic widely used in veterinary medicine that inhibits the action of bacterial DNA gyrase, resulting in anti-bacterial effects. This study was performed to examine whether enrofloxacin has modulatory and anti-inflammatory activity on immune cells. A few studies have reported the anti-inflammatory effects of enrofloxacin. In this study, we used mouse spleen cells treated with lipopolysaccharide (LPS) and examined the effects of enrofloxacin. Several assays were performed in LPS-treated spleen cells after the enrofloxacin treatment. Enrofloxacin inhibited the metabolic activity and mitochondrial membrane potential of LPS-treated spleen cells significantly. On the other hand, enrofloxacin did not alter the proportion of the subsets in spleen cells, and did not induce cell death. The production of tumor necrosis factor-alpha in LPS-treated spleen cells was inhibited by enrofloxacin. Overall, enrofloxacin had modulatory activity in spleen cells treated with LPS. These data may broaden the use of enrofloxacin as an antibiotic with anti-inflammatory activity in veterinary clinics.

Bacteriocins: Assay, Biochemistry, and Mode of Action

  • Paik, Hyun-Dong
    • Preventive Nutrition and Food Science
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    • v.1 no.2
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    • pp.269-277
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    • 1996
  • Bacteriocins are proteins produced by a heterogeneous group of bacteria that have a bactericidal effect on closely related organisms. Recently, bacteriocins from lactic acid bacteria and other food-related organisms have been the subject of much research because of their potential as food biopreservatives. Various modifications of agar plate diffusion assays are the most widely used methods even though the limitations of such assays are generally recognized. The ability to obtain a concentrated crude preparation on bacteriocin by optimizing production parameters greatly simplifies recovery of bacteriocin on subsequent purification steps. Some studies performed to optimize bacteriocins have been purified to homogeneity, and the amino acid sequences of many of these purified bacteriocins have been determined. Obtaining characterization data on purified bacteriocin will minimize the risk of overlapping of research and confusion on identification of these compounds. Several me-chanisms leading to cell death have been hypothesized. These include depletion of the proton motive force(PMF) across the cell membrane: RNase and/or DNase activity within the sensitive cell; and pore formation and lysis of sensitive cells at the cell membrane.

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Production of Azadirachtin from Plant Tissue Culture: State of the Art and Future Prospects

  • Prakash, Gunjan;Bhojwani, Sant S.;Srivastava, Ashok K.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.4
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    • pp.185-193
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    • 2002
  • With Increasing awareness towards environment-friendly and non-toxic pesticide azadirachtin obtained from neon tree (Azadirachta indica) is gaining more and more importance. Its broad-spectrum activity, Peculiar mode of action. eco-friendly and non-toxic action towards beneficial organisms has offered many advantages over chemical pesticides. All currently use commercial formulations based on azadirachtin contains azadirachtin extracted from seeds of naturally grown whole plants which is labour intensive process depending upon many uncontrollable geographical and climatic factors. Plant tissue culture can be a potential process for the pro-duction, offering consistent, stable and controlled supply of this bioactive compound, However the research on tissue culture aspects of production are in preliminary stage and requires culture and process optimization for the development of a commercially viable process. This review states the present status and future challenges of plant tissue culture for azadirachtin production.

Conduction Block of the Primary Afferent Fibers by Topically Applied Allyl Isotheocyanate

  • Shin, Hong-Kee;Kim, Kee-Soon
    • The Korean Journal of Physiology
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    • v.28 no.2
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    • pp.123-132
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    • 1994
  • The present study was undertaken to elucidate the desensitization of cutaneous receptors and the conduction block of the afferent nerves induced by direct application of allyl isotheocyanate (mustard oil) to the receptive field (RF) or onto the afferent nerve, respectively. Dorsal horn cell responses to mechanical stimulations of RF were completely suppressed when mustard oil was applied to either the afferent nerve or the whole area of RF. C-fiber responses of dorsal horn cells were more susceptive to mustard oil than A-fiber activities. This was confirmed by the experiment in which the compound action potentials recorded from rat tibial nerve before and after topical application of mustard oil were compared. The higher the concentration of mustard oil and the longer the application time, the more powerful desensitization or conduction block was induced. From the results of the present study, it is suggested that the desensitization of the afferent fiber and sensory receptors induced by mustard oil results mainly from the conduction block of C-fiber in the primary afferent nerve.

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A Selection Method of Optimal Digital Low-pass Differentiator for Spike Detection of Surface Motor Unit Action Potential (표면 운동단위 활동전위 스파이크 검출을 위한 최적의 디지털 저역통과 미분기 선정 방법)

  • Lee, Jin;Kim, Sung-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.10
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    • pp.1951-1958
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    • 2011
  • The objective of this study is to analyze the performance of digital low-pass differentiators(LPD) and then to provide a method to select effective LPD filter, for detecting spikes of surface motor unit action potentials(MUAP). The successful spike detection of MUAPs is a first important step for EMG signal decomposition. The performances of simple and weighted LPD(SLPD and WLPD) filters are analyzed based on different filter lengths and varying MUAPs from simulated surface EMG signals. The SNR improving coefficient and effective MUAP duration range from the analysis results can be used to select proper LPD filters under the varying conditions of surface EMG.

New Phytoformula (CAS) Containing the Roots of Cyathula officinalis, Achyranthes japonica and Sophora subprostrata Inhibits Collagen-induced Arthritis in Mice

  • Lee, Jae Hyung;Lim, Hyun;Kwon, Yong Soo;Kim, Hyun Pyo
    • Natural Product Sciences
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    • v.20 no.1
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    • pp.17-21
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    • 2014
  • The combined new phytoformula (CAS), a mixture (5 : 3 : 2, w/w/w) of the ethanol extracts of the roots of C. officinalis and A. japonica, and the n-butanol fraction of the S. subprostrata strongly inhibited arthritic severity score as well as IL-6 production in serum of collagen-induced arthritic mice. Histological observation also indicated that the CAS-treated group showed less breakdown of joint cartilage of the collagen-treated mice. In contrast, C. officinalis alone or a combination of A. japonica and S. subprostrata did not show significant inhibitory action on the same animal model. Thus, it is thought that CAS possesses a synergistic inhibitory action on arthritic condition. All these results strongly suggest that CAS may be a potential anti-arthritic agent.

Probenecid inhibit $\alpha$-adrenergic receptor mediated vasoconstriction (프로베네시드의 혈관 알파 수용체 길항 작용)

  • Kim, Sung-Jin
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2001.11a
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    • pp.98-98
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    • 2001
  • It has been suggested that hyperuricemia is related to the development of essential hypertension. Hypertensive patients with hyperuricemia has decreased glomerular filtration activity as compared to normotensive patients with hyperuricemia. These studies indicates uric acid concentrations in blood is associated with hypertension, Probenecid is an uricosuric agent which decreases uric acid reabsorption at the proximal tubule. Recently, we have shown that probenecid exerts anti-hypertensive action in Spontaneously Hypertensive Rats. Considering these results, I have designed a series of experiments to explore potential mechanism of antihypertensive action, of probenecid. In isolated rat thoracic aorta. probenecid significantly prevented phenylephrine-induced contraction of the blood vessel. When endothelium removed blood vessels were used, probenecid produced same effect as the intact blood vessels, indicating that probenecid directly act through the ${\alpha}$ -adrenergic receptor in vascular smooth muscles rather than through endothelium. These results suggest that one of the mechanism of antihypertensive effects of probenecid is due to the direct inhibition of ${\alpha}$ -adrenergic receptor in blood vessels.

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Analysis of meridian response by bio-energy transmission (생체에너지(기) 전달에 의한 경락 반응 분석)

  • 정석준;이용흠;정동명
    • Proceedings of the IEEK Conference
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    • 2002.06e
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    • pp.141-144
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    • 2002
  • Acupuncture effect principle on meridians is what physical stimulation does on general physiology so that it gets into new equilibrium from the fallen function state of human body. However, it is generally accepted that western medicine has regarded the action passageway of various kinds stimulation as nerve fluids tissue or nerve-endocrine-immune system. These regard any action for all meridians as a response to the stimulation. These are not treatments for transmission of the energy. This paper compares the change of electric potential when operator's bio-energy is passed on and when is not. As a result of it, the effect of acupuncture is different when a operator's bio-energy is passed on to meridians and it isn't. Therefore, it means that the general acupuncture is more effective than the insulation one. Moreover, we could certify that there is close relation between an operator's energy transmission and acupuncture effect.

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