• The Korean Journal of Physiology
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• 제7권2호
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• pp.31-37
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• 1973

The effects of ethanol extacts of aconite root (Aconitum koreanum) on mean arterial pressure, heart rate, pulse pressure, and respiration were investigated and also studied the effect on electrical activation of the hypothalamus in cats. From the present experiment the following results were obtained. 1) On administering 5 mg or 10 mg aconite extracts per kg of body weight, the mean arterial blood pressure declined markedly possibly as the result of negative inotropic and chronotropic effects of aconite. 2) From the enhanced pressor responses to intravenously injected epinephrine, the existance of vasodilatory effect of the aconite was suggested. 3) After administration of aconite extract, no significant differences were observed in the presser responses to carotid occlusion and to electrical stimulation of the hypothalamus. It is, therefore, concluded that the aconite extract exerts no significant effect on the excitability of hypothalamus as well as medullary cardiovascular center of cats. 4) After administration of $5{\sim}10$ mg/kg aconite extracts, respiratory rate was increased while depth of respiration decreased. On the otherhand, respiratory rate was markedly decreased by injection of 20 mg/kg aconite into animal.

• 정신신체의학
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• 제18권1호
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• pp.3-10
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• 2010

뚜렛 증후군은 주로 아동기에 발생하는 만성적인 운동 및 음성 틱을 주소로 하는 질환이다. 기저핵-시상-피질 회로에서의 이상이 비자발성 틱의 병태생리에 중요한 역할을 하는 것으로 생각된다. 뚜렛 증후군은 흔히 주의력 결핍 과잉행동장애나 강박장애와 병존한다. 경두개 자기자극술은 연구용으로 많이 사용되는 신경생리학적 기법이다. 이 기법이 피질의 활성을 변화시킬 수 있다는 증거들이 많아서, 반복적 경두개 자기자극술은 피질의 활성도를 바꾸어서 결과적으로 내재한 서로 연결된 피질-피질하 회로에 영향을 주기 위하여 치료적 목적으로도 사용된다. 우리는 본 논문에서 경두개자극술의 여러 신경생리학적 변인들과 임상적 응용에 관하여 기존의 연구보고들을 고찰하여 보고자 한다.

• The Korean Journal of Physiology and Pharmacology
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• 제10권2호
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• pp.59-64
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• 2006

The effects of $Zn^{2+}$ on spontaneous glutamate and GABA release were tested in mechanically dissociated rat CA3 pyramidal neurons which retained functional presynaptic nerve terminals. The spontaneous miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs, respectively) were pharmacologically isolated and recorded using whole-cell patch clamp technique under voltage-clamp conditions. $Zn^{2+}$ at a lower concentration $(30{\mu}M)$ increased GABAergic mIPSC frequency without affecting mIPSC amplitude, but it decreased both mIPSC frequency and amplitude at higher concentrations $({\ge}300{\mu}M)$. In contrast, $Zn^{2+}$ (3 to $100{\mu}M$) did not affect glutamatergic mEPSCs, although it slightly decreased both mIPSC frequency and amplitude at $300{\mu}M$ concentration. Facilitatory effect of $Zn^{2+}$ on GABAergic mIPSC frequency was occluded either in $Ca^{2+}$-free external solution or in the presence of $100{\mu}M$ 4-aminopyridine, a non-selective $K^{+}$ channel blocker. The results suggest that $Zn^{2+}$ at lower concentrations depolarizes GABAergic nerve terminals by blocking $K^{+}$ channels and increases the probability of spontaneous GABA release. This $Zn^{2+}$-mediated modulation of spontaneous GABAergic transmission is likely to play an important role in the regulation of neuronal excitability within the hippocampal CA3 area.

• The Korean Journal of Physiology and Pharmacology
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• 제4권1호
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• pp.9-14
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• 2000

$K^+$ currents play multiple roles in the excitability of dorsal root ganglion (DRG) neurons. Influences on these currents change the shape of the action potential, its firing threshold and the resting membrane potential. In this study, whole cell configuration of patch clamp technique had been applied to record the blocking effect of capsaicin, a lipophilic alkaloid, on the delayed rectifier $K^+$ current in cultured small diameter DRG neurons of adult rat. Capsaicin reduced the amplitude of $K^+$ current in dose dependent manner, and the concentration-dependence curve was well described by the Hill equation with $K_D$ value of $19.1{\mu}M.$ The blocking effect of capsaicin was reversible. Capsaicin $(10 {\mu}M)$ shifted the steady-state inactivation curve in the hyperpolarizing direction by about 15 mV and increased the rate of inactivation. The voltage dependence of activation was not affected by capsaicin. These multiple effects of capsaicin may suggest that capsaicin bind to the region of $K^+$ channel, participating in inactivation process.

• The Korean Journal of Physiology and Pharmacology
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• 제8권1호
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• pp.33-41
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• 2004

We developed a cardiac cell model to explain the phenomenon of mechano-electric feedback (MEF), based on the experimental data with rat atrial myocytes. It incorporated the activity of ion channels, pumps, exchangers, and changes of intracellular ion concentration. Changes in membrane excitability and $Ca^{2+}$ transients could then be calculated. In the model, the major ion channels responsible for the stretch-induced changes in electrical activity were the stretch-activated channels (SACs). The relationship between the extent of stretch and activation of SACs was formulated based on the experimental findings. Then, the effects of mechanical stretch on the electrical activity were reproduced. The shape of the action potential (AP) was significantly changed by stretch in the model simulation. The duration was decreased at initial fast phase of repolarization (AP duration at 20% repolarization level from 3.7 to 2.5 ms) and increased at late slow phase of repolarization (AP duration at 90% repolarization level from 62 to 178 ms). The resting potential was depolarized from -75 to -61 mV. This mathematical model of SACs may quantitatively predict changes in cardiomyocytes by mechanical stretch.

• The Korean Journal of Physiology and Pharmacology
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• 제23권6호
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• pp.427-448
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• 2019

Nociceptin/orphanin FQ (N/OFQ) and its receptor, nociceptin opioid peptide (NOP) receptor, are localized in brain areas implicated in depression including the amygdala, bed nucleus of the stria terminalis, habenula, and monoaminergic nuclei in the brain stem. N/OFQ inhibits neuronal excitability of monoaminergic neurons and monoamine release from their terminals by activation of G protein-coupled inwardly rectifying $K^+$ channels and inhibition of voltage sensitive calcium channels, respectively. Therefore, NOP receptor antagonists have been proposed as a potential antidepressant. Indeed, mounting evidence shows that NOP receptor antagonists have antidepressant-like effects in various preclinical animal models of depression, and recent clinical studies again confirmed the idea that blockade of NOP receptor signaling could provide a novel strategy for the treatment of depression. In this review, we describe the pharmacological effects of N/OFQ in relation to depression and explore the possible mechanism of NOP receptor antagonists as potential antidepressants.

• Structural Monitoring and Maintenance
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• 제2권3호
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• pp.213-236
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• 2015

The paper presents an investigation into the mode conversion and scattering characteristics of guided waves at delaminations in laminated composite beams. A three-dimensional (3D) finite element (FE) model, which is experimentally verified using data measured by 3D scanning laser vibrometer, is used in the investigation. The study consists of two parts. The first part investigates the excitability of the fundamental anti-symmetric mode ($A_0$) of guided wave in laminated composite beams. It is found that there are some unique phenomena, which do not exist for guided waves in plate structures, make the analysis become more complicated. The phenomena are observed in numerical study using 3D FE simulations. In the second part, several delaminated composite beams are studied numerically to investigate the mode conversion and scattering characteristics of the $A_0$ guided wave at delaminations. Different sizes, locations and through-thickness locations of the delaminations are investigated in detail. The mode conversion and scattering phenomena of guided waves at the delaminations are studied by calculating reflection and transmission coefficients. The results show that the sizes, locations and through-thickness locations of the delaminations have significant effects on the scattering characteristics of guided waves at the delaminations. The results of this research would provide better understanding of guided waves propagation and scattering at the delaminations in the laminated composite beams, and improve the performance of guided wave damage detection methods.

• Journal of Medicine and Life Science
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• 제15권2호
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• pp.62-66
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• 2018

A-type $K^+$ ($I_A$) channels are transiently activated in the suprathreshold membrane potential and then rapidly inactivated. These channels play roles to control the neuronal excitability in pyramidal neurons in hippocampi. We here electrophysiologically tested if regulatory functions of $I_A$ channels might be targeted by acute activation of glutamatergic synaptic transmission in cultured hippocampal neurons(DIV 6~8). The application of high KCl in recording solutions(10 mM, 2 min) to increase presynaptic glutamate release, significantly reduced the peak of somatic $I_A$ without changes of gating kinetics. This indicates that neuronal excitation induced by the enhancement of synaptic transmission may process with distinctive signaling cascades to affect voltage-dependent ion channels in hippocampal neurons. Therefore, it is possible that short-lasting enhancement of synaptic transmission is functionally restricted in local synapses without effects on intracellular signaling cascades affecting a whole neuron, efficiently and rapidly enhancing synaptic functions in hippocampal network.

• The Journal of Korean Physical Therapy
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• 제34권3호
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• pp.98-103
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• 2022

Purpose: New therapeutic approaches have emerged to improve gait ability in patients with brain damage, such as action observation learning (AOT), auditory cueing, motor imagery etc. We attempted to investigate the effects of AOT with auditory cueing (AOTAC) on gait function in patients with stroke. Methods: The eighteen stroke patients with a unilateral hemiparesis were randomly divided into three groups; the AOTAC, AOT, and control groups. The AOTAC group (n=8) received training via observing a video that showed normal gait with sound of footsteps as an auditory cue; the AOT group (n=6) receive action observation without auditory stimulation; the control group (n=5) observed the landscape video image. Intervention time of three groups was 30 minutes per day, five times a week, for four weeks. Gait parameters, such as cadence, velocity, stride length, stance phase, and swing phase were collected in all patients before and after each training session. Results: Significant differences were observed among the three groups with respect to the parameters, such as cadence, velocity, stride length, and stance/swing phase. Post-hoc analysis indicated that the AOTAC group had a greater significant change in all of parameters, compared with the AOT and control groups. Conclusion: Our findings suggest that AOTAC may be an effective therapeutic approach to improve gait symmetry and function in patients with stroke. We believe that this effect is attributable to the change of cortical excitability on motor related to cortical areas.

• The Journal of Korean Physical Therapy
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• 제33권2호
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• pp.91-96
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• 2021

Purpose: This study investigated the effects of cryotherapy on the ankle joint muscle strength and balance ability in stroke patients with ankle joint muscles. Methods: In this study, 20 patients with chronic stroke were recruited from a rehabilitation hospital. The patients were divided into two groups: a cryotherapy group (10 patients) and a control group (10 patients). The cryotherapy group performed sit-to-stand training for 15 minutes and then cryotherapy for the minutes. In the control group, after sit-to-stand training for 15 minutes, blocked cryotherapy was provided for three minutes. In both groups, the interventions were provided five times a week for three weeks. The strength of the ankle joint muscles was measured before and after the training using the Biodex systems 3. The static balance ability was measured using balancia software, and the dynamic balance ability was measured by performing the sit-to-stand test (FTSST) five times. Results: After the training periods, the cryotherapy group showed significant improvement in the ankle dorsiflexor strength, ankle plantarflexor strength, weight distribution of the affected side, and FTSST compared to the control group (p<0.05). Conclusion: Based on these results, cryotherapy could be considered an effective method to improve the strength of ankle joint muscles. Cryotherapy improves muscle strength as it increases the motor neuron excitability. Therefore, cryotherapy may be considered to improve the strength of the ankle joint muscles of stroke patients.