• Journal of Life Science
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• v.16 no.1
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• pp.114-119
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• 2006

The purpose of this study was to determine effects of the Ga-As (Gallium-Arsenide) Dens-Bio laser on mechanically injured sciatic nerves of rats. The improvement of the injured rat sciatic nerve was evaluated by measuring of nerve conduction velocity and amplitude of compound muscle action potential. The sciatic nerves of forty male Sprague-Dawley rats were compressed with hemostatic forceps for 30 seconds. The experimental group was divided into 4 subgroups according to the duration of treatment. Lower power infrared laser irradiation was done transcutaneously to the injured sciatic nerve area, 3 minutes daily to each of four treatment groups for 1, 3, 5, and 7 weeks, respectively. Compound muscle action potential and nerve conduction velocity of sciatic nerve were obtained before nerve injury and at 1, 3, 5, and 7 weeks after injury. There were significant difference of the nerve conduction velocity and amplitudes of compound muscle action potential between the treatment group and non-treatment group at 1, 3, and 5 weeks after laser treatment. However, there were no differences found between the electrophysiologic parameters that were measured after 7 weeks in two groups. There was significant correlation between the increment of compound muscle action potential and nerve conduction velocity after time course according to laser treatment. In conclusion, the low power laser treatment had improved the sciatic nerve function, and therefore these results may provide the basic data to clarify the neurological recovery and treatment after incomplete peripheral nerve injury.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.4
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• pp.305-312
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• 2015

Paeonol is a major component found in the Paeoniaceae family such as Paeonia suffruticosa Andrews. Paeonia suffruticosa Andrews has traditionally been used to enhance blood flow and relieve joint pain in east Asian countries including China, Korea and Japan. Current research has shown that paeonol blocked the voltage-gated sodium channel and L-type calcium channel. However, there is a lack of research to reveal the relation between cardiac function and blockade of ion channels by paeonol. Therefore, the aim of this study is to investigate whether paeonol has anti-arrhythmic effects via modulating cardiac ion channels. It is collected that the effects of paeonol on multiple ion channels such as the fast sodium channel and L-type calcium channel from published papers. To incorporate the information on multi-channel block, we computed the effects using the mathematical cardiac model of the guinea-pig and rat ventricular cells (Noble 1998 and 1991 model) and induced early after-depolarizations (EADs) to generate an arrhythmia in the whole heart. Paeonol slightly shortened the action potential duration in the normal cardiac ventricular action potential by the inhibition of sodium channel and L-type calcium channel. Paeonol presented the protective effect from EADs by the inactivation of sodium channel but not L-type calcium channel. Paeonol did not show any changes when it treated on normal ventricular cells through the inhibition of sodium channel, but the protective effect of paeonol through sodium channel on EADs was dose-dependent. These findings suggest that paeonol and its original plant may possess anti-arrhythmic activity, which implies their cardioprotective effects.

• The Korean Journal of Physiology
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• v.17 no.2
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• pp.169-176
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• 1983

It is well known that the acupuncture has been used effectively for the relief of certain types of pain. Although the precise mechanism of action of acupuncture analgesia is unknown, it is generally accepted that their analgesic properties are related to the activation of endogenous opiate system in central nervous system. And it is suggested that pain-relieving properties of acupunture may be related to a stimulation of peripheral nerve underlying the acupuncture point on the skin. However, the efficacy of acupuncture has no relationship between the site of pain and the acupuncture point. Consequently, the present study was undertaken to investigate electroacupuncture analgesia in relation to the site of peripheral nerve stimulation. Cats were decerebrated ischemically and the flexion reflex as an index of pain was elicited by stimulating the sural nerve (20V, 0.5 msec duration) and recored as a compound action potential from the nerve innervated to the posterior biceps femoris muscle in the ipsilateral hindlimb. Bilateral common peroneal nerve and contralateral superficial radial nerve were selected as the site of peripheral nerve stimulation. For the stimulation of peripheral nerve, a stimulus of 20 V intensity, 2 msec-duration and 2 Hz-frequency was applied for 60 min respectively. The results obtained are summarized as follows: 1) Both stimulation of contralateral common peronal nerve and contralateral superficial radial nerve did not change the flexion reflex and there were no significant differences between them. 2) Stimulation of ipsilateral common peroneal nerve markedly depress the flexion reflex, the effect being reversed by naloxone application. These results suggest that stimulation of ipsilateral common peroneal nerve has the analgesic effect but both stimulation of contralteral common peroneal nerve and contralateral superficial radial nerve to the pain site where flexion reflex was elicited have no analgesic effect.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.249-255
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• 2012

A cochlear implant system uses charge-balanced biphasic pulses that are known to reduce tissue damage than monophasic pulses. In this study, we investigated effect of pulse pattern on neural responses using a computer model, based on the Hodgkin-Huxley equation. Electric pulse phase, pulse duration, and phase gap have been systematically varied to characterize auditory nerve responses. The results show that neural responses, dynamic range and threshold are represented as a function of stimulus patterns and duration. The results could greatly extend to develop more efficient cochlear implant stimulation.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.2
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• pp.135-144
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• 2022

An antidiabetic drug, rosiglitazone is a member of the drug class of thiazolidinedione. Although restrictions on use due to the possibility of heart toxicity have been removed, it is still a drug that is concerned about side effects on the heart. We here examined, using Chinese hamster ovary cells, the action of rosiglitazone on Kv1.5 channels, which is a major determinant of the duration of cardiac action potential. Rosiglitazone rapidly and reversibly inhibited Kv1.5 currents in a concentrationdependent manner (IC₅₀ = 18.9 μM) and accelerated the decay of Kv1.5 currents without modifying the activation kinetics. In addition, the deactivation of Kv1.5 current, assayed with tail current, was slowed by the drug. All of the results as well as the usedependence of the rosiglitazone-mediated blockade indicate that rosiglitazone acts on Kv1.5 channels as an open channel blocker. This study suggests that the cardiac side effects of rosiglitazone might be mediated in part by suppression of Kv1.5 channels, and therefore, raises a concern of using the drug for diabetic therapeutics.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.3
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• pp.119-125
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• 2010

We investigated the effects of a hot-water extract of Artemisia iwayomogi, a plant belonging to family Compositae, on cardiac ventricular delayed rectifier $K^+$ current ($I_K$) using the patch clamp technique. The carbohydrate fraction AIP1 dose-dependently increased the heart rate with an apparent $EC_{50}$ value of $56.1{\pm}5.5\;{\mu}g/ml$. Application of AIP1 reduced the action potential duration (APD) in concentration-dependent fashion by activating $I_K$ without significantly altering the resting membrane potential ($IC_{50}$ value of $APD_{50}$: $54.80{\pm}2.24$, $IC_{50}$ value of $APD_{90}$: $57.45{\pm}3.47\;{\mu}g/ml$). Based on the results, all experiments were performed with $50\;{\mu}g/ml$ of AIP1. Pre-treatment with the rapidly activating delayed rectifier $K^+$ current ($I_{Kr}$) inhibitor, E-4031 prolonged APD. However, additional application of AIP1 did not reduce APD. The inhibition of slowly activating delayed rectifier $K^+$ current ($I_{Ks}$) by chromanol 293B did not change the effect of AIP1. AIP1 did not significantly affect coronary arterial tone or ion channels, even at the highest concentration of AIP1. In summary, AIP1 reduces APD by activating $I_{Kr}$ but not $I_{Ks}$. These results suggest that the natural product AIP1 may provide an adjunctive therapy of long QT syndrome.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.99-102
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• 1997

A neural spike sorting technique has been developed that also has the capability of template learning. A system of software has been written that first obtains the templates by learning, and then performs the sorting of the spikes into single units. The spike sorting can be done in real time. The template learning consists of spike detection based on the discrete Haar transform (DHT), feature extraction by clustering of spike amplitude and duration, classification based on rms error, and fabrication of templates. The developed algorithms can be implemented into real time systems using digital signal processors.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.708-711
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• 2017

전기적 신호의 이상으로 발생하는 심방 부정맥은 심방세동으로 발전하는 대표적 심장 질환이다. 이러한 원인에는 세포 내 이온 채널의 유전적 결함으로 인한 기전이 알려져 있다. 지속적인 연구로 밝혀진 대표적인 유전적 질환 중 하나로서 KCNH2 유전자 돌연변이가 있다. 본 연구에서는 KCNH2 유전자 돌연변이가 심방부정맥을 유발하는 연관성연구를 기반으로 심실에서의 심장 질환 발현 연관성을 확인하고 심실부정맥과 심실세동 가능성을 예측하였다. 이를 위해 Ten tusscher 세포 모델에 KCNH2 유전자의 N588K, L532P 변이를 적용하여 2차원과 3차원 시뮬레이션을 진행하였다. wild-type(WT)과 mutant-type(MT)의 전기전도 패턴을 비교했다. 그 결과 WT의 전도파형이 일찍 자가소멸(self-termination) 되는 것과 대조적으로 MT는 회귀성 파형이 유지되었다(WT : 3.6초간 유지, MT : 지속적). 따라서 본 연구를 통해 KCNH2 유전자 돌연변이가 심실 조직의 취약성 (Action Potential Duration 감소, WT : 270 ms, N588K : 130 ms, L532P : 100 ms)을 증가시켜 부정맥의 요인이 됨을 확인하였다.

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1364-1369
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• 2017

There is a growing demand for natural sleep aids due to various side effects of long-term administration of pharmacological treatments for insomnia. Honey has been reported to exhibit numerous potential health benefits, and it is hypothesized that honey may favorably affect insomnia treatment. Therefore, this study was performed to investigate the possible hypnotic effect of clover honey (CH) and to determine its in vivo mechanism. The total flavonoid content (TFC) of CH and fractions extracted with ethylacetate (EtOAc) and $H_2O$ was measured. The pentobarbital-induced sleep test using $GABA_A$-benzodiazepine (BZD) agonists and antagonists was conducted to evaluate the potential mechanism of action behind the sedative-hypnotic activity of CH in mice. The results showed that administration of 500 and 1,000 mg/kg of CH significantly (p<0.01) reduced the sleep latency to a level similar to that of diazepam (DZP, 2 mg/kg), and 1,000 mg/kg of CH significantly (p<0.01) prolonged the sleep duration, which was comparable to that of DZP (2 mg/kg). Administration of the EtOAc fraction with a higher TFC significantly reduced the sleep latency at 50 to 200 mg/kg and prolonged the sleep duration at 100 to 200 mg/kg, which were comparable to those after administration of DZP (2 mg/kg). However, co-administration of CH and EtOAc with flumazenil, a specific $GABA_A-BZD$ receptor antagonist, blocked the hypnotic effect. Our findings suggest that the hypnotic activity of CH may be attributed to allosteric modulation of $GABA_A-BZD$ receptors. The TFC of CH is expected to be a key factor that contributes to its hypnotic effect.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.3
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• pp.143-147
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• 2002

Granule cells in dentate gyrus of hippocampus relay information from entorhinal cortex via perforant fiber to pyramidal cells in CA3 region. Their electrical activities are known to be closely associated with seizure activity as well as memory acquisition. Since action potential is a stereotypic phenomena which is based on all-or-none principle of $Na^+$ current, the neuronal firing pattern is mostly dependent on afterpotentials which follows the stereotypic $Na^+$ spike. Granule cells in dentate gyrus show afterdepolarization (ADP), while interneurons in dentate gyrus have afterhyperpolarizaton. In the present study, we investigated the ionic mechanism of afterdepolarization in hippocampal dentate granule cell. Action potential of dentate granule cells showed afterdepolarization, which was characterized by a sharp notch followed by a depolarizing hump starting at about $-49.04{\pm}1.69\;mV\;(n=43,\;mean{\pm}SD)$ and lasting $3{\sim}7$ ms. Increase of extracellular $Ca^{2+}$ from 2 mM to 10 mM significantly enhanced the ADP both in amplitude and in duration. A $K^+$ channel blocker, 4-aminopyridine (4-AP, 2 mM), enhanced the ADP and often induced burst firings. These effects of 10 mM $Ca^{2+}$ and 4-AP were additive. On the contrary, the ADP was significantly suppressed by removal of external $Ca^{2+},$ even in the presence of 4-AP (2 mM). A $Na^+$ channel blocker, TTX (100 nM), did not affect the ADP. From these results, it is concluded that the extracellular $Ca^{2+}$ influx contributes to the generation of ADP in granule cells.