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- 검색키워드
- 주제어 : Inhibitory postsynaptic potentials (검색결과 4 건)
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Hahm, Eu-Teum,Seo, Jung-Woo,Hur, Jin-Young,Cho, Young-Wuk The Korean Society of Pharmacology 2010 The Korean Journal of Physiology & Pharmacology Vol.14 No.3
Reactive oxygen species (ROS), which include hydrogen peroxide ($H_2O_2$), the superoxide anion (${O_2}^-{\cdot}$), and the hydroxyl radical ($OH{\cdot}$), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of $H_2O_2$ on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at -60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM $H_2O_2$ gradually potentiated mIPSCs. This potentiating effect of $H_2O_2$ was blocked by the pretreatment with either 10,000-unit/mL catalase or $300-{\mu}M$ N-acetyl-cysteine. The potentiating effect of $H_2O_2$ was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N -(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.
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함의틈,서정우,허진영,조영욱 대한약리학회 2010 The Korean Journal of Physiology & Pharmacology Vol.14 No.3
Reactive oxygen species (ROS), which include hydrogen peroxide (H2O2), the superoxide anion (O2−․), and the hydroxyl radical (OH․), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of H2O2 on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at −60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM H2O2 gradually potentiated mIPSCs. This potentiating effect of H2O2 was blocked by the pretreatment with either 10,000-unit/mL catalase or 300-μM N-acetyl-cysteine. The potentiating effect of H2O2 was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N-(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.
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Uta Daisuke,Hattori Tsuyoshi,Yoshimura Megumu 대한배뇨장애요실금학회 2020 International Neurourology Journal Vol.24 No.2
Purpose: Alpha1-adrenoceptors participate in improving storage symptoms of male lower urinary tract symptoms. However, the mechanism of action of these compounds remains unclear. The goal of the present study was to clarify the effect of α1- adrenoceptor antagonists on γ-aminobutyric acid (GABA)/glycine-mediated outward currents of the inhibitory postsynaptic current (IPSC) in substantia gelatinosa (SG) neurons from the lumbosacral spinal cord in rats. Methods: Male adult Sprague-Dawley rats were used. Blind whole-cell patch-clamp recordings were performed in SG neurons from isolated spinal cord slice preparations. IPSCs were recorded in individual SG neurons to which naftopidil (100μM), tamsulosin (100μM), silodosin (30μM), or prazosin (10μM) were applied sequentially with intervening washout periods. Strychnine (2μM), bicuculline (10μM), or tetrodotoxin (TTX)(1μM) were added before naftopidil. Individual outward currents were analyzed. Results: The bath application of naftopidil, yielded outward IPSCs in 13 of 52 SG neurons. The naftopidil response was unchanged in the presence of TTX. Regression analysis of the outward currents between the 1st and 2nd applications of naftopidil revealed a Pearson correlation coefficient of 0.996 with a line slope of 0.983. The naftopidil-induced outward current was attenuated in the presence of strychnine and/or bicuculline. The GABA/glycine-mediated outward currents induced by tamsulosin, silodosin, and prazosin were smaller than those obtained with naftopidil. Conclusions: Naftopidil-induced GABA/glycine-mediated outward currents in a subset of SG neurons prepared from the L6– S1 level of rat spinal cord. The results indicated that α1-adrenoceptor antagonists, particularly naftopidil, induce neural suppression (in part) by mediating hyperpolarization. The response is associated with glycinergic and/or GABAergic neural transmission. Naftopidil may suppress the micturition reflex and improve urinary storage symptoms as a subsidiary effect resulting from hyperpolarization in SG neurons of the spinal cord.
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Yiming Shen,Seong Kyu Han,Pan Dong Ryu 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.4
The hypothalamic paraventricular nucleus (PVN) contains two types of neurons projecting to either the rostral ventrolateral medulla (PVNRVLM) or the intermediolateral horn (IML) of the spinal cord (PVNIML). These two neuron groups are intermingled in the same subdivisions of the PVN and differentially regulate sympathetic outflow. However, electrophysiological evidence supporting such functional differences is largely lacking. Herein, we compared the electrophysiological properties of these neurons by using patch-clamp and retrograde-tracing techniques. Most neurons (>70%) in both groups spontaneously fired in the cell-attached mode. When compared to the PVNIML neurons, the PVNRVLM neurons had a lower firing rate and a more irregular firing pattern (p < 0.05). The PVNRVLM neurons showed smaller resting membrane potential, slower rise and decay times, and greater duration of spontaneous action potentials (p < 0.05). The PVNRVLM neurons received greater inhibitory synaptic inputs (frequency, p < 0.05) with a shorter rise time (p < 0.05). Taken together, the results indicate that the two pre-sympathetic neurons differ in their intrinsic and extrinsic electrophysiological properties, which may explain the lower firing activity of the PVNRVLM neurons. The greater inhibitory synaptic inputs to the PVNRVLM neurons also imply that these neurons have more integrative roles in regulation of sympathetic activity.
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