• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.6
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• pp.81-87
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• 1983

The body surface ECG(electrocardiogram) is produced by the electric fields caused by the propagation of action potentials within the myocardial cells. The repolarization phase of the action potential is very sensitive to factors of clinical importance. Therefore, in this paper of the inverse electrocardiography, we studied a method of estimating the uniform action potentials during repolarization phase from the body surface ECG using digital signal identification techniques. The estimated action potential of a normal was similar to that of clinical data in the repolarization phase.

• BMB Reports
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• v.28 no.3
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• pp.221-226
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• 1995

Dopamine mediates inhibitory responses in Helix aspersa neurons from the right parietal lobe ("F-lobe") of the circumoesophageal ganglia. The effects appeared as a dose-dependent hyperpolarization of the plasma membrane and a decrease in the occurrence of spontaneous action potentials. The average hyperpolarization with 5 ${\mu}m$ dopamine was -12 mV (${\pm}1.5$mV, S.D., n=12). Dopamine also modulated the currents 'responsible for shaping the action potentials in these neurons. When dopamine was added and action potentials were triggered by an injection of current, the initial depolarization was slowed, the amplitude and the duration of action potentials were decreased, and the after-hyperpolarization was more pronounced. The amplitude and the duration of action potential were reduced about 15 mV and about 13% by 5 ${\mu}m$ dopamine, respectively. The effects of dopamine on the resting membrane potentials and the action potentials of Helix neurons were dose-dependent in the concentration range 0.1 ${\mu}m$ to 50 ${\mu}m$. In order to show 1) that the effects of dopamine were mediated by dopamine receptors rather than by direct action on ionic channels and 2) which type of dopamine receptor might be responsible for the various effects, we assayed the ability of mammalian dopamine receptor antagonists, SCH-23390 (antagonist of D1 receptor) and spiperone (antagonist of D2 receptor), to block the dopamine-dependent changes. The D1 and D2 antagonists partially inhibited the dopamine-dependent hyperpolarization and the decrease in action potential amplitude. They both completely blocked the decrease in action potential duration and the increase in action potential after-hyperpolarization. The dopamine-induced slowdown of the depolarization in the initial phase of the action potentials was less effected by SCH-23390 and spiperone. From the results we suggest 1) that Helix F-lobe neurons may have a single type of dopamine receptor that binds both SCH-23390 and spiperone and 2) that the dopamine receptor of Helix F-lobe neurons may be homologous with and primitive to the family of mammalian dopamine receptors.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.1 no.1
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• pp.17-29
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• 2003

This study was investigated the effects on functional recovery of eccentric exercise-induced muscle damage by phonophoresis transdermal permeation of piroxicam gel and observed the change of amplitude at muscle action potential. Through eccentric exercise-induced muscle damage, performed healthy men and women take eccentric resistance exercise and measured action, potentials. The subjects were divided into three groups of four men each 24 hour, 48 hour, 72 hour. The results of this were as follows: 1. Change of maximal action potential at maximal voluntary contraction : The phonophoresis group was increase more than control group and gel group. 2. Change of average action potential at maximal voluntary contraction : The gel group was increase more than control group and phonophoresis group. 3. Change of maximal action potential at pain subthreshold voluntary contraction : The phonophoresis group was increase more significantly than control group and gel group. 4. Change of average action potential at pain subthreshold voluntary contraction : The phonophoresis group was increase more significantly than control group and gel group. In conclusion, the change of muscle action potential amplitude by eccentric exercise-induced muscle damage showed that the phonophoresis by pulsed ultrasound of piroxicam gel was improved the recovery of muscle function.

• The Korean Journal of Pharmacology
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• v.30 no.2
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• pp.181-190
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• 1994

In rat atrium the characteristics of purinergic receptors were investigated by observing the effects of some purinergic receptor agonists and antagonists on action potential and contractile force. The statistically significant effects of $ATP(10^{-6}{\sim}10^{-3}M)$ and adenosine $(10^{-6}{\sim}10^{-3}M)$ on normal action potential characteristics were a dose-dependent shortening of action potential duration $(APD_{90})$ by both agents and hyperpolarization by $ATP(10^{-4},10^{-3}M)$. $CAP(10^{-8}{\sim}10^{-4}M)$, an $A_1$ adenosine receptor agonist, shortened $(APD_{90})$ markedly in a dose-dependent manner and these effects were almost abolished by $DPCPX\;(10^{-6}\;M), an $A_1$, adenosine receptor antagonist, but not affected by $DMPX(2{\times}10^{-6}\;M)$, an $A_2$ adenosine receptor agonist. On the other hand, CGS $21680(10^{-7}{\sim}10^{-4}M)$, an $A_2$ adenosine receptor agonist, elicited a slight shortening of $(APD_{90})$ and these effects were inhibited by DPCPX but persisted in the presence of DPMX. Adenosine $(10^{-6}{\sim}10{\-4}\;M)$ decreased the basal contraction of atrial muscle in a dose-dependent manner and these effects were not inhibited by DMPX but by DPCPX. These results suggests that purinergic receptor agonists depress the cardiac activity by a short ening of action potential duration and this effect is mostly mediated by $A_1$ adenosine receptors in rat atrium.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.169-177
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• 1987

The effects of higenamine were investigated in the single atrial and ventricular myocyte of the guinea pig by using patch clamp method. The results obtained were as follows: 1) Isoprenaline which is known to be ${\beta}-agonist$ increased the duration of action potential and calcium current in ventricular cells. 2) Higenamine also increased the duration of action potential and calcium current in ventricular myocytes. And its effect was blocked by propranolol. 3) In the atrial cells, isoprenaline showed ${\beta}-agonist$ effects, which were increasing the duration of action potential and calcium current same as in ventricular cells. 4) Higenamine, however, showed the opposite effects of ${\beta}-agonist$ which were decreasing the duration of action potential and calcium current. The above results suggest that higenamine has the typical ${\beta}-agonist$ effect in ventricular cells but inhibitory effect in atrial cells and this effect on atrium could be due to the reduction of calcium current.

• The Korean Journal of Physiology
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• v.19 no.2
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• pp.127-137
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• 1985

The present study was undertaken in order to investigate effect of ethanol extract of Rehmanniae radix(RREE) on electrophysiology of sinus node and papillary muscle. Rehmanniae radix is a herbal medicine which has been known to have diuretic, antipyretic, hemopoietic and cardiotonic effects. Action potentials were recorded by means of glass capillary microelectrode(technique) in rabbit sinoatrial nodal cells and papillary muscle cells which were superperfused with either tyrode solution or tyrode solutions containing different amount of RREE. The results obtained were as follows ; 1) In both central and peripheral nodal cells maximum diastolic potential (MDP) and amplitude of action potential (APA) were not affected by RREE. 2) Action potential duration as expressed $APD_{60}$(time to 60% repolarization) of central and peripheral pacemaker cells were significantly prolonged following perfusion with tyrode solution containing 0.1% RREE. 3) The rates of spontaneous firing from central pecemaker cell were decreased by RREE at concentration of 0.05% and 0. 1% while spontaneous rhythm of perinodal cell was decreased by 0.1% RREE. 4) The action potential duration of papillary muscle as expressed $APD_{60}$ were prolonged by 0.1% RREE.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.1
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• pp.9-17
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• 2014

Electrical compound action potential (ECAP) can be recorded on cochlear implant. This study will investigate stimulation and recording to enhance the efficacy of ECAP. 34 articles was used. We analyzed pulse and stimulating condition, artifact suppression, recording condition. The cathod-leading biphasic pulse was used with as short as possible pulse width and inter phase gap for the efficacy of neural firing, stable threshold and preventing neural degeneration. Around C-level was stimulated to apical, middle and basal turn of cochlea. Artifact was eliminated by forward-masking, template-subtraction technique. For clearer waveform, we need to change distance between stimulating and recording electrode, the gain of amplification, number of average.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.562-570
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• 2010

The transmission phenomenon of neuron action potential due to exterior stimulation is somewhat identical to electrical reaction configuration. Therefore, I tried to analyze the transmission status of membrane excitation, by introducing electrical concept to this issue in this paper. First of all, I researched the complex electrical status of axon, and then simplified the electrical circuit into pure resistance circuit under the assumption that it was reasonable in practice. And I derived the transmission status of exciting action potential through the simplified circuits using electical theory and mathematical concept. I calculated overshoot potential of a certain portion and then confirmed that it excited neighbor portion and made it to be transmitted using the proposed data which was typical in point of biological and electrical view to verify this result.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.137-143
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• 2022

Purpose : The purpose of this study was to evaluate the reliability analysis of the deep tendon reflex by using electromyography (EMG). Methods : The study was tested on 30 volunteers who are women in their 20s. Using an electronic reflective hammer of EMG, deep tendon reflex was measured on all subjects with the participation of three trained physical therapists as raters. First, the subjects were comfortably seated on a table with their knees bent at 90 °. The three raters tapped the electric hammer at intervals of 10 seconds to avoid habituation until a total of 10 compound muscle action potential records were collected. Intraclass correlation coefficients (ICCs) were calculated to assess the inter-rater reliability of the deep tendon reflex with the use of EMG. The items of analysis included amplitude (mV), latency (ms), duration (ms), and area (mV × ms) of the compound evoked potentials. Results : Based on the average records of 10 compound muscle action potential, excellent reliability (ICC: .912) was achieved in terms of area, and there was good reliability in terms of latency (ICC: .795) and duration (ICC: .800). In the shortest latency of the compound muscle action potential, good reliability was achieved in terms of amplitude (ICC: .865), duration (ICC: .781), and area (ICC: .832). In the amplitude of peak-to-peak of compound muscle action potential, excellent reliability was recorded in terms of amplitude (ICC: .924), and good reliability was recorded in terms of duration (ICC: .801) and area (ICC: .874). Conclusion : The findings in this study indicate that electromyography via an electric hammer is a reliable method of assessing and measuring deep tendon reflexes. Especially, it may be an excellent gauge in the area of average values of the compound muscle action potentials and the amplitude of peak-to-peak of compound muscle action potentials.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.199-212
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• 1983

The inhibition/influences of adenine compounds on the heart have been described repeatedly by many investigators, since the first report by Druny and Szent-Gyorgyi [1929]. These studies have shown that adenosine and adenine nucleotides have an over-all effect similar to that of acetylcholine [ACh] by slowing and weakening the heartbeat. The basic cellular and membrane events underlying the inhibitory action of adenosine on sinus rate, however, are not well understood. Furthermore, the physiological role of adenosine in regulation of the heartbeat remains still to be elucidated. Therefore, this study was undertaken in order to examine the response of rabbit SA node to adenosine and to compare the response to that of ACh. Isolated SA node preparation, whole atrial pair, or left atrlal strip was used in each experiment. Action potentials of SA node were recorded through the intracellular glass microelectrodes, which were filled with 3M KCI and had resistance of 30-50 M. All experiments were performed in a bicarbonate-buffered Tyrode solution which was aerated with 3% $CO_2-97%$ $O_2$ gas mixture and kept at $35^{\circ}C$. Spontaneous firing rate of SA node at 35C [Mean + SEM, n=16] was 154 + 3.3 beats/min. The parameters of action potentials were: maximum astolic potential [MDP], -731.7mV: overshoot [OS], 9 + 1.4mV; slope of pacemaker potential [SPP], 94 3.0mV/sec.Adenosine suppressed the firing rate of SA node in a dose dependent manner. This inhibitory effect appeared at the concentration of $10^{-6}M$ and was potentiated in parallel with the increase in adenosine concentration. Changes in action potential by adenosine were dose-dependent increase of MDP and decrease of SPP until $10^{-4}$. Above this concentration, however, the amplitude of action potential decreased markedly due to the simultaneous decrease of both MDP and OS. All these effects of adenosine were not affected by pretreatment of atropine [2mg/l] and propranolol [$5{\times}10^{-6}M$]. ACh [$10^{-6}M$] responses on action potential were similar to those of adenosine by increasing MDP and decreasing SPP. These effects of ACh disappeared by pretreatment of atropine [2mg/1]. Inhibition/effects of adenosine and ACh on sinus rate were enhanced synergistically with the simultaneous administration of adenosine and ACh. Marked decrease of overshoot potential was the most prominent feature on action potential. Dipyridamole [DPM], which is known to block the adenosine transport across cell membrane, definitely potentiated the action of adenosine . Adenosine suppressed the sinus rate and atrial contractility in the same dosage range, even in the reserpinized preparation. Above` results suggest that adenosine suppresses pacemaker activity, like ACh, by acting directly on the membrane of SA node, increasing MDP and decreasing SPP.