• Journal of Life Science
• /
• v.9 no.2
• /
• pp.15-18
• /
• 1999

Tempting to further understand the molecular mechanism of pharmacological action of ethanol, we investigated the acute effects of ethanol on the GABA-activated current (IGABA) of the cultured Sprague-Dawley rat hippocampal neurons in primary culture using the whole-cell patch-clamp technique. Patch-clamp recordings revealed that ethanol potentiated the Cl- current in a concentration-dependent manner(1-300mM) in the majority of the cell studied. This study demonstrates that ethanol can potentiate IGABA in mammalian central neurons.

• Smart Structures and Systems
• /
• v.13 no.4
• /
• pp.567-585
• /
• 2014

The piezoelectric transverse $d_{15}$ shear sensing mechanism is firstly assessed experimentally for a cantilever smart sandwich plate made of a piezoceramic axially poled patched core and glass fiber reinforced polymer composite faces. Different electrical connections are tested for the assessment of the sensor performance under a varying amplitude harmonic (at 24 Hz) force. Also, the dynamic response of the smart sandwich composite structure is monitored using different acquisition devices. The obtained experimentally sensed voltages are compared to those resulting from the benchmark three-dimensional piezoelectric coupled finite element simulations using a commercial code where realistic features, like equipotential conditions on the patches' electrodes and mechanical updating of the clamp, are considered. Numerically, it is found that the stiffness of the clamp, which is much softer than the ideal one, has an enormous influence on the sensed voltage of its adjacent patch; therefore, sensing with the patch on the free side would be more advantageous for a cantilever configuration. Apart from confirming the latter result, the plate benchmark experimental assessment showed that the parallel connection of its two oppositely poled patches has a moderate performance but better than the clamp side patch acting as an individual sensor.

• The Korean Journal of Physiology and Pharmacology
• /
• v.11 no.1
• /
• pp.15-20
• /
• 2007

To investigate whether hydrogen peroxide($H_2O_2$) affects intestinal motility, pacemaker currents and membrane potential were recorded in cultured interstitial cells of Cajal(ICC) from murine small intestine by using a whole-cell patch clamp. In whole cell patch technique at $30^{\circ}C$, ICC generated spontaneous pacemaker potential under current clamp mode(I=0) and inward currents(pacemaker currents) under voltage clamp mode at a holding potential of -70 mV. When ICC were treated with $H_2O_2$ in ICC, $H_2O_2$ hyperpolarized the membrane potential under currents clamp mode and decreased both the frequency and amplitude of pacemaker currents and increased the resting currents in outward direction under voltage clamp mode. Also, $H_2O_2$ inhibited the pacemaker currents in a dose-dependent manner. Because the properties of $H_2O_2$ action on pacemaker currents were same as the effects of pinacidil(ATP-sensitive $K^+$ channels opener), we tested the effects of glibenclamide(ATP-sensitive $K^+$ channels blocker) on $H_2O_2$ action in ICC, and found that the effects of $H_2O_2$ on pacemaker currents were blocked by co- or pre- treatment of glibenclamide. These results suggest that $H_2O_2$ inhibits pacemaker currents of ICC by activating ATP-sensitive $K^+$ channels.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.27 no.1
• /
• pp.112-117
• /
• 2013

We studied the modulation of pacemaker activities by Samchulkunbi-tang (SCKB) in cultured interstitial cells of Cajal (ICC) from murine small intestine with the whole-cell patch-clamp technique. Externally applied SCKB produced membrane depolarization in the current-clamp mode. The pretreatment with $Ca^{2+}$-free solution and thapsigargin, a $Ca^{2+}$-ATPase inhibitor in endoplasmic reticulum, abolished the generation of pacemaker potentials and suppressed the SCKB-induced action. The application of flufenamic acid (a nonselective cation channel blocker) abolished the generation of pacemaker potentials by SCKB. However, the application of niflumic acid (a chloride channel blocker) did not inhibit the generation of pacemaker potentials by SCKB. In addition, the membrane depolarizations were inhibited by not only GDP-${\beta}$-S, which permanently binds G-binding proteins, but also U-73122, an active phospholipase C inhibitor. These results suggest that SCKB modulates the pacemaker activities by nonselective cation channels and external $Ca^{2+}$ influx and internal $Ca^{2+}$ release via G-protein and phospholipase C-dependent mechanism. Therefore, the ICC are targets for SCKB and their interaction can affect intestinal motility.

• Korean Journal of Acupuncture
• /
• v.18 no.1
• /
• pp.143-156
• /
• 2001

Modulatory effect of cAMP-PKA system on inhibitory- and excitatory herbs-induced ion currents were investigated by nystatin-perforated patch clamp method under voltage-clamp condition. Ion currents induced by Bupleuri radix and Coptidis rhizoma were not affected by cAMP-PKA system. Ion current induced by Ecliptae herba was partially inhibited by cAMP-PKA system. Ion currents induced by Aconiti tuber and Boshniakiae herba were inhibitory modulated and ion current induced by Zingiberis rhizoma was excitatory modulated by cAMP-PKA system. Modulation of cAMP-PKA system on ion currents induced by Ginseng radix was fluctuated. In this results, it can be seen generally that excitatory herbs-induced ion currents were modulated by cAMP-PKA system while cAMP-PKA system did not affect inhibitory herbs-induced ion currents.

• Journal of Life Science
• /
• v.9 no.2
• /
• pp.82-85
• /
• 1999

The effects of ethanol on 5-hydrosytryptamine(5-HT3) receptor-mediated ion current were evaluated in whole-cell patch-clamp recordings from NCB-20 neuroblastoma cells. The physiologic and pharmacologic properties of 5-HT-activated ion current in NCB-20 cells indicated that it was mediated by 5-HT3 receptors. Ethanol(25-100mM) potentiated 5-HT3 receptor-mediated current in a concentration-dependent manner.

• Korean Journal of Acupuncture
• /
• v.20 no.4
• /
• pp.17-29
• /
• 2003

목적:천수근은 염증성 관절염과 염증성 장 질환 등에 사용되어왔다. 천수근이 중심회백질 신경세포에서 하행성 진통작용에 미치는 영향을 연구하였다. 방법: 중심회백질 신경세포를 분리하여 전위고정하에서 nystatin-perforated patch-clamp technique을 시행하였다. 결과: 천수근에 의하여 유발되는 이온전류는 GABA, glycine, 그리고 glutamate 수용체를 모두 활성화시켰다.

• The Journal of the Korean dental association
• /
• v.38 no.4 s.371
• /
• pp.378-384
• /
• 2000

• The Korean Journal of Physiology and Pharmacology
• /
• v.15 no.5
• /
• pp.285-289
• /
• 2011

Shilajit, a medicine herb commonly used in Ayurveda, has been reported to contain at least 85 minerals in ionic form that act on a variety of chemical, biological, and physical stressors. The substantia gelatinosa (SG) neurons of the trigeminal subnucleus caudalis (Vc) are involved in orofacial nociceptive processing. Shilajit has been reported to be an injury and muscular pain reliever but there have been few functional studies of the effect of Shilajit on the SG neurons of the Vc. Therefore, whole cell and gramicidin-perfotrated patch clamp studies were performed to examine the action mechanism of Shilajit on the SG neurons of Vc from mouse brainstem slices. In the whole cell patch clamp mode, Shilajit induced short-lived and repeatable inward currents under the condition of a high chloride pipette solution on all the SG neurons tested. The Shilajit-induced inward currents were concentration dependent and maintained in the presence of tetrodotoxin (TTX), a voltage gated $Na^+$ channel blocker, CNQX, a non-NMDA glutamate receptor antagonist, and AP5, an NMDA receptor antagonist. The Shilajit-induced responses were partially suppressed by picrotoxin, a $GABA_A$ receptor antagonist, and totally blocked in the presence of strychnine, a glycine receptor antagonist, however not affected by mecamylamine hydrochloride (MCH), a nicotinic acetylcholine receptor antagonist. Under the potassium gluconate pipette solution at holding potential 0 mV, Shilajit induced repeatable outward current. These results show that Shilajit has inhibitory effects on the SG neurons of Vc through chloride ion channels by activation of the glycine receptor and $GABA_A$ receptor, indicating that Shilajit contains sedating ingredients for the central nervous system. These results also suggest that Shilajit may be a potential target for modulating orofacial pain processing.

• Journal of Korean Neurosurgical Society
• /
• v.39 no.3
• /
• pp.215-220
• /
• 2006

Objective : Tyrosine kinase inhibitors may be useful in the management of cerebral vasospasm. It has not yet been reported whether L-type $Ca^{2+}$ channels playa role in tyrosine kinase inhibitors-induced vascular relaxation of cerebral artery. This study was undertaken to clarify the role of L-type $Ca^{2+}$ channels in tyrosine kinase inhibitors-induced vascular relaxation, and to investigate the effect of tyrosine kinase inhibitors on L-type $Ca^{2+}$ channels currents in freshly isolated smooth muscle cells from rat basilar artery. Methods : The isolation of rat basilar smooth muscle cells was performed by special techniques. The whole cell currents were recorded by whole cell patch clamp technique in freshly isolated smooth muscle cells from rat basilar artery. Results : Patch clamp studies revealed a whole-cell current which resembles the L-type $Ca^{2+}$ current reported by others. The amplitude of this current was decreased by nimodipine and increased by Bay K 8644. Genistein[n=5], tyrphostin A-23[n=3]. A-25[n=6] $30{\mu}M$ reduced the amplitude of the L -type $Ca^{2+}$ channel current in whole cell mode. In contrast, diadzein $30{\mu}M$ [n=3]. inactive analogue of genistein, did not decrease the amplitude of the L-type $Ca^{2+}$ channels current. Conclusion : These results suggest that tyrosine kinase inhibitors such as genistein, tyrphostin A-23, A-25 may relax cerebral vessel through decreasing level of intracellular calcium, [$Ca^{2+}$]i, by inhibition of L-type $Ca^{2+}$ channel.