• Title/Summary/Keyword: Action Potentials

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EFFECT OF D-PROPRANOLOL ON TRANSMEMBRANE ACTION POTENTIAL OF CARDIAC PAPILLARY MUSCLE OF CAT (고양이 유두근의 활동전압에 미치는 d-propranolol의 영향)

  • Lee, Jong-Heun;Kim, Joong-Soo
    • The Journal of the Korean dental association
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    • v.16 no.7 s.110
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    • pp.531-536
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    • 1978
  • Adult cats were light anesthetized with ethyl ether and heart was removed fastly. cardiac papillary muscle was dissected from heart in organ bath con taining Tyrode solution saturated with 95% O₂+5% CO₂, and prepared papillary muscles were placed in Tyrode solution that was continuously circulated and gassed with 95% O₂+5% CO₂at 32℃. The isolated papillary muscle was stimulated continuously with platinum pin electrode at frequency of 15/min and 90/min by means of electric stimulator and transmembrane action potentials were recorded with microelectrdes on the oscilloscope. The drug used was d-propranolol and its concentration was 0.5, 1.5 and 5.0 mg/L. The results obtained were as follows: 1. D-propranolol increased the threshold voltage of papillary muscle and raised by average of 213.6% of control. 2. D-propranolol had no effect on duration of action potential. 3. Conduction time of isolated papillary muscle was increased by d-propranolol and its effect was prominent at frequency of 90/min. 4. the maximum upstroke velocity was decreased by d-propranolol and its effect was dose-depndent decrease.

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Design of a Digital Signal Processing System for Analysis of Tendon Reflex Response (T-반사 응답의 분석을 위한 디지탈 신호 처리 시스템의 설계)

  • 김재국;권도철
    • Journal of Biomedical Engineering Research
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    • v.17 no.2
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    • pp.221-226
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    • 1996
  • Tendon reflex responses generated from mechanical stimulus had been studied for quantitative analysis of activity of tendon reflex, especially patellar tendon reflex responses are known to be a criterion for diagnosing the L3 or L4 radiculopathy. In this paper, we developed a digital signal processing system for analysis of the tendon reflex response. The system parameter, i.e., $\textit{sampling frequency, pre-amplification gain, input channel and filter bank}$ are selected by Using software switches. From the view points of flexibility, the system hardware is connected to an IBM PC for analyzing the tendon reflex parameters, amplitude, latency duration We applied the proposed system to the analysis of the patellar tendon reflex reponses. In the experiment, we measured latency, duration, amplitude of the reflex action potentials generated from vastus medialis, vastus lateralis and rectus femoris that compose quadriceps, and the measured data are analyzed througll the ANOVA test which has 5% significant level. As a result, we showed that the mean amplitude of reflex action potential at the vastus lateralis is larger than any other muscle and the mean latency of the reflex action potential at the rectus femoris is shorter than any other muscle.

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The relationship between nerve conduction studies and neuropathic pain in sciatic nerve injury due to intramuscular injection

  • Fidanci, Halit;Ozturk, Ilker
    • The Korean Journal of Pain
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    • v.34 no.1
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    • pp.124-131
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    • 2021
  • Background: Sciatic nerve injury due to intramuscular injection (SNIII) is still a health problem. This study aimed to determine whether there is a correlation between neuropathic pain and electrodiagnostic findings in SNIII. Methods: Patients whose clinical and electrodiagnostic findings were compatible with SNIII participated in this retrospective cohort study. Compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the sural, superficial peroneal, peroneal, and tibial nerves were graded from 1 to 4. Leeds assessment of neuropathic symptoms and signs scale (LANSS) was applied to all patients. Results: Forty-eight patients were included in the study, 67% of whom had a LANSS score ≥ 12. Sural SNAP amplitude abnormalities were present in 8 (50%) out of 16 patients with a LANSS score < 12, and 28 (87.5%) out of 32 patients with a LANSS score ≥ 12, with significant differences between the groups (P = 0.011). There was a positive correlation between the LANSS score and the sural SNAP amplitude grading (P = 0.001, r = 0.476). A similar positive correlation was also found in the LANSS score and the tibial nerve CMAP amplitude grading (P = 0.004, r = 0.410). Conclusions: This study showed a positive correlation between the severity of tibial nerve CMAP/sural SNAP amplitude abnormality and LANSS score in SNIII. Neuropathic pain may be more common in SNIII patients with sural nerve SNAP amplitude abnormality.

After Contraction in Isolated Cardiac Muscle (심룡근(心朧筋)의 반복수축현상(反復收縮現象)에 관(關)하여)

  • Ryo, Ung-Yun;Brooks, Chandler Mcc.
    • The Korean Journal of Physiology
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    • v.1 no.1
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    • pp.67-72
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    • 1967
  • Present paper is attempted to introduce the phenomenon of 'after contraction' in isolated cardiac-muscle. Papillary muscles were removed from cat right ventricle and were used as a preparation. The muscle strip was Placed in tissue bath which is kept in steady temperature of around $25^{\circ}C$ and was perfuced by Tyrode solution, saturated with 95% $O_2$ and 5% $CO_2.$ under the condition of high calcium (8.2-10.0 mM/l), low sodium (72.4-70.0 mM/l) perfusion with the administration of epinephrine (1-2 mg/l) into tile tissue bath normally triggered muscle contraction was followed by oscillatory, repetitive contractions - after contraction. The phenomenon of after contraction was augumented by decrease in tissue bath temperature and by increase in number of preceding beats and in driving rate. Authors were able to maintain the phenomenon in prominent and steady state giving proper experimental conditions such as fixed bath temperature (ranged from $22^{\circ}C\;to\;27^{\circ}C$), suitable driving rate (20 per minute in average) and perfusion of high calcium, loll sodium and 1-2 mg/l of epinephrine. In some preparations, the strength of after contraction (second contraction) reached up-to 80% of normally triggered contraction and five repetitive contractions were observed as largest number of after contractions. Intracellular action potential measured in the muscle which was beating regulary showing steady after contraction revealed no oscillating after potential in most parts of the muscle but in few cases oscillating changes of after potentials were detectable. In electrogram of the muscle preparation recorded by means of contact electrode prominent, oscillating after potentials were observable when the recorder was set at highest sensitivity. It still is not clear that whether after contraction is the phenomenon which corresponds to those changes in action potential, oscillating after potential, of the muscle preparation. Possible mechanism of the phenomenon of after contraction relating with after potential changes was proposed. Detailed results obtained from further studies on after contraction and concrete discussion on the phenomenon will be reported by authors.

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The Semantic Structure of Synaptic Activation, Likened to Cho Ji-Hoon's Poem 'Line' (조지훈의 시 「선(線)」으로 비유되는 시냅스 활성화의 의미 구조)

  • Park, In-kwa
    • The Journal of the Convergence on Culture Technology
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    • v.3 no.4
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    • pp.21-26
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    • 2017
  • The purpose of this study was to analyze the structure of neurophysiological healing in Cho Ji-Hoon's poem "Line" and to use it in literature therapy program. Research shows that action potentials in the human body represent the mind. In other words, the electric charges appear to be the signs of the mind, and the action potentials of all the charges of the human body are integrated together to systematize the mind. Cho Ji-Hoon's poem "Line" resembles the process of collecting, analyzing, synthesizing and reproducing information, which is the function of the human neurophysiological synapse. This is a useful form of poetry in terms of its application to literary therapy programs. If we develop such a form of literary therapy program as Cho Ji-Hoon's poem, it will be more effective in healing process.

Clinical and Electrophysiological Features of the Patients with POEMS Syndrome (POEMS 증후군의 임상적, 전기생리학적 특성)

  • Min, Joo-Hong;Hong, Yoon-Ho;Lee, Kwang-Woo
    • Annals of Clinical Neurophysiology
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    • v.6 no.1
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    • pp.14-19
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    • 2004
  • Backgrounds and objectives: POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome is the rare cause of polyneuropathy. Although the polyneuropathy is essential for the diagnosis of the disease, the pattern of electrodiagnostic abnormalities has not been characterized in detail. The purpose of this study was to elucidate the features of nerve conduction abnormalities in POEMS syndrome. Methods: We reviewed the medical records and nerve conduction studies (NCS) of 12 consecutive patients with POEMS. Results: A total of 68 motor and 46 sensory nerves were examined. Compound muscle action potentials (CMAPs) and sensory nerve action potentials were abnormally attenuated or not elicited in majority of motor and sensory nerves (80.88% in motor, and 82.6% in sensory nerves). Frequency of the nerves with no potential was significantly higher in lower limbs than in upper limbs (p<0.01 in both motor and sensory nerves), and CMAP amplitude was more reduced in lower limbs than in upper limbs (p<0.01). Conduction slowing was very frequently observed with 95% and 76% of motor and sensory nerves, respectively, having the abnormally reduced values of conduction velocity. Distal motor latencies were abnormally prolonged in 75% of motor nerves, and terminal latency indices were significantly higher in patients than in normal controls (p < 0.05). Conduction block was observed only in 5% of motor nerves. Conclusions: NCS in POEMS syndrome showed characteristic patterns, in which conduction abnormalities were more frequently and severely affected in the lower limbs, and more predominantly in the intermediate nerve segments than in the distal portions. The recognition of these characteristic patterns may be helpful in early diagnosis of polyneuropathy in POEMS syndrome.

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Contractile and Electrical Responses of Guinea-pig Gastric Smooth Muscle to Bradykinin

  • Kim, Chul-Soo;Jun, Jae-Yeoul;Kim, Sung-Joon;So, In-Suk;Kim, Ki-Whan
    • The Korean Journal of Physiology
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    • v.29 no.2
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    • pp.233-241
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    • 1995
  • The nonapeptide bradykinin has been shown to exhibit an array of biological activities including relaxation/contraction of various smooth muscles. In order to investigate the effects of bradykinin on the contractility and the electrical activity of antral circular muscle of guinea-pig stomach, the isometric contraction and membrane potential were recorded. Also, using standard patch clamp technique, the $Ca^{2+}-activated$ K currents were recorded to observe the change in cytosolic $Ca^{2+}$ concentration. $0.4 {\mu}M$ bradykinin induced a triphasic contractile response (transient contraction-transient relaxation-sustained contraction) and this response was unaffected by pretreatment with neural blockers (tetrodotoxin, atropine and guanethidine) or with apamin. Bradykinin induced hyperpolarization of resting membrane potential and enhanced the amplitude of slow waves and spike potentials. The enhancement of spike potentials was blocked by neural blockers. Both the bradykinin-induced contractions and changes in membrane potential were reversed by the selective $B_2$-receptor antagonist $(N{\alpha}-adamantaneacetyl-_{D}-Arg-[Hyp, Thy,_{D}-Phe]-bradykinin)$. In whole-cell patch clamp experiment, we held the membrane potential at -20 mV and spontaneous and transient changes of Ca-activated K currents were recorded. Bradykinin induced a large transient outward current, consistent with a calcium-releasing action of bradykinin front the intracellular calcium pool, because such change was blocked by pretreatment with caffeine. Bradykinin-induced contraction was also blocked by pretreatment with caffeine. From these results, it is suggested that bradykinin induces a calciumrelease and contraction through the $B_{2}$ receptor of guinea-pig gastric smooth muscle. Enhancement of slow wave activity is an indirect action of bradykinin through enteric nerve cells embedded in muscle strip.

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CORRELATIONS BETWEEN HIPPOCAMPAL THETA RHYTHM AND INTRACELLULAR CHARACTERISTICS OF PYRAMIDAL NEURONS (해마 theta 리듬과 pyramidal neuron의 세포내 특성과의 상관관계)

  • Kwon, Oh-Heung;Kim, Young-Jin;Nam, Soon-Hyeun;Kim, Hyeun-Jung;Lee, Man-Gee;Cho, Jin-Hwa;Choi, Byung-Ju
    • Journal of the korean academy of Pediatric Dentistry
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    • v.25 no.4
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    • pp.671-682
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    • 1998
  • Electrophysiological phenomena of pyramidal cells in the CA1 area of the dorsal hippocampus were recorded from and filled with neurobiotin in anesthetized rats. The electropharmacological properties of membrane as well as the cellular-synaptic generation of rhythmic slow activity (theta) were examined. The intracellular response characteristics of these pyramidal cells were distinctly different from responses of interneurons. Pyramidal cells had a high resting membrane potential, a low input resistance, and a large amplitude action potential. A afterhyperpolarization was followed a single action potential. Most of pyramidal cells did not display a spontaneous firing. Pyramidal cells displayed weak inward rectification and anodal break excitation. The slope of the frequency-current relation was 53.4 Hz/nA for the first interspike interval and 15.9 Hz/nA for the last intervals, suggesting the presence of spike frequency adaptation. Neurobiotin-filled neurons showed pyramidal morphology. Cells were generally bipolar dendritc processes ramifying in stratum lacunosum-moleculare, radiatum, and oriens. Commissural stimulation discharged pyramidal cells, followed by excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs). The frequency of theta-related membrane potential oscillation was voltage-independent in pyramidal neurons. At strong depolarization levels (less than 30 mV) pyramidal cells emitted sodium spike oscillation, phase-locked to theta. The observations provide direct evidence that theta-related rhythmic hyperpolarization of principal cells is brought by the rhythmically discharging interneurons. Furthermore, the findings in which interneurons were also paced by rhythmic inhibitory postsynaptic potentials during theta suggest that they were periodically hyperpolarized by their GABAergic septal afferents.

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Experimental Study for Nerve Regeneration Using Tubes Filled with Autogenous Skeletal Muscle in a Gap of Rabbit Sciatic Nerves (백색 가토 좌골 신경의 신경 결손부위에서 자가 골격근 충진 도관을 이용한 신경재생 연구)

  • Lee, Jun-Mo;Shin, Sung-Jin;Seo, Jeong-Hwan;Song, Chang-Ho
    • Archives of Reconstructive Microsurgery
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    • v.12 no.1
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    • pp.1-12
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    • 2003
  • The bridging of nerve gaps is still one of the major problems in peripheral nerve surgery. To evaluate the role of silicon tube in nerve regeneration, gaps were made by resection of tibial components of sciatic nerves of twenty-five New Zealand rabbits. The gaps were divided into five groups. In group I, the tibial components of sciatic nerves were isolated and the incision immediately closed. In group II, 1-cm segments of the nerve were removed and the silicon tubes filled with autogenous skeletal muscle were sutured in place. In group III, 1-cm segments of the nerve were removed and the silicon tubes filled without muscle were sutured in place. In group IV, 2-cm segments of the nerve were removed and the silicon tubes filled with autogenous skeletal muscle were sutured in place. In group V, 2-cm segments of the nerve were removed and the silicon tubes filled without muscle were sutured in place. At 16th week, the eletromyography, the light and transmission electron microscopy were performed. Nerve conduction study stimulating sciatic nerve proximal to the lesion and recording at gastrocnemius muscle showed that the compound muscle action potentials of the group II with 1 cm nerve defect filled with muscle were higher amplitudes than the group III without muscle. Compound muscle action potentials of the group IV with 2 cm defect filled with muscle showed similar results in comparison with the group V. The light and transmission electron microscpy showed that a good morphological pattern of nerve regeneration in 1 cm gap than 2 cm and in gap with muscle than gap without muscle.

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A Study on Integrated Multimicroelectrode Array (집적회로형 다중 초미소 전극 배예에 관하여)

  • ;Bel
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.17 no.6
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    • pp.58-64
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    • 1980
  • A new type of multimicroelectrode array has been developed using integrated circuit technology in order to record action potentials from nervous systems. The size and pattern of the electrode array are determined accurately in a frow $\mu$m range by optical photolithogaphy. The electrical characteristics of the integrated microelectrode array were investigated. The practical applications of this electrode array in recording action potentials from a ventral nerve of a cockroach are shown.

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