纳洛酮对小鼠海马CA1区神经元缺血再灌注损伤干预效果的观察

目的进一步验证脑缺血再灌注损伤实验动物模型的可行性,初步探讨纳洛酮再灌注后干预对脑缺血再灌注损伤的影响,探索脑缺血再灌注损伤时纳洛酮后干预的最佳时机。方法采用结扎双侧颈总动脉小鼠脑缺血再灌注损伤模型,分别观察纳洛酮再灌注后干预对海马CA1区神经元存活细胞数和细胞形态的影响。结果纳洛酮治疗组小鼠海马CA1区存活细胞数明显高于缺血再灌注对照组,差异有统计学意义(P<0.05),变性细胞率明显低于缺血再灌注对照组,差异有统计学意义(P<0.05),而与假手术组比较差异无统计学意义(P>0.05),纳洛酮治疗组各组内比较差异无统计学意义。纳洛酮各组与缺血再灌注对照组比较变性坏死细胞明显减少,细胞形态接近正常,间质水肿得到改善。结论从形态学的角度,纳洛酮后干预确实能减轻脑缺血再灌注损伤,在1.5h内不同时间给予纳洛酮的干预效果没有明显差别。     

铅对大鼠海马神经元钠电流的抑制作用

目的　铅对神经系统有损害作用 ,钠通道是神经元产生和传递电信号的重要枢纽 ,故研究铅对大鼠海马CA1区神经元钠电流 (INa)的影响。方法全细胞膜片钳技术。结果　醋酸铅可浓度依赖地抑制INa,1 ,1 0 ,50和 1 0 0 μmol·L-1 醋酸铅对INa的抑制率分别为 (8.2± 0 .8) % ,(2 0 .9± 2 .6) % ,(51 .8±4.8) %和 (66 .4±5 .7) %。此外 ,它还与电压呈依赖关系 ,50 μmol·L-1 醋酸铅可使INa的激活曲线显著右移 ,但不改变斜率因子 ,还可使INa的失活曲线显著左移。结论　铅可抑制INa的激活过程 ,可促进INa的失活过程。铅改变了细胞膜的电压感应 ,这可能是铅损伤海马神经元的作用机制之一     

氟哌利多对大鼠脑缺血海马CA1区锥体细胞持续钠通道电流的影响

目的 :研究氟哌利多对大鼠脑缺血海马CA1区锥体细胞持续钠通道电流的影响。方法 :酶消化法急性分离SD大鼠 (10～ 14d)海马CA1区锥体细胞 ,通过低氧和无糖法制备神经元缺血模型 ,全细胞膜片钳技术记录氟哌利多对脑缺血时锥体细胞持续性钠通道电流的影响。结果 :在钳制电压 (Vh) 10 5mV ,刺激电压 (Vt) 30mV条件下 ,神经元缺血 3min和 5min后持续钠电流显著增强。 3、10和 30μmol·L-1氟哌利多能明显抑制缺血引起的持续钠电流增强 (P <0 .0 1,n =7) ,不同浓度氟哌利多的作用间无显著差别。结论 :临床麻醉浓度的氟哌利多能够抑制体外脑缺血时海马神经元持续钠电流增强 ,对缺血神经元有保护作用。     

红霉素对小鼠海马神经元电压依赖性钾电流的影响

目的:研究红霉素对小鼠海马神经元电压依赖性钾电流的影响。方法:采用分离新生小鼠海马细胞和全细胞膜片钳技术的方法,观察给予红霉素前后海马神经元细胞电压依赖性钾电流的变化和电流-电压曲线的改变。结果:红霉素可抑制小鼠海马细胞电压依赖性钾电流,使电流峰值由(810.67±250.86)pA下降至(529.96±171.83)pA(P<0.05);给予系列去极化脉冲刺激海马神经元,随着刺激电压强度的增强,钾外向电流增加,电压-电流曲线右移,但不改变曲线的形态。结论:红霉素可抑制小鼠海马神经元电压依赖性钾电流,并可能通过中枢机制来影响其调节胃肠运动的效应。     

芍药苷对醋酸铅诱导海马神经元凋亡及Bcl-2/Bax蛋白表达的影响

目的 探讨芍药苷(paeoniflorin,PF)对醋酸铅诱导海马神经元凋亡及Bcl-2/Bax蛋白表达的影响。方法 分离培养胎鼠海马神经元细胞,细胞免疫荧光染色鉴定纯度。MTT测定海马神经元细胞活力以确定醋酸铅最适造模浓度及时间,同时筛选合适剂量PF干预海马神经元凋亡。依据MTT测定结果,分为空白组、模型组和20,40,80 μmol·L^-1 PF组干预海马神经元细胞,作用24 h后,加醋酸铅染毒,检测细胞色素C (cytochrome C,Cyt-C)含量、线粒体膜电位及细胞内Ca²⁺浓度。流式细胞仪检测细胞凋亡情况,Western blotting测定海马神经元细胞中caspase-3、cleaved-caspase-3、caspase-8、cleaved-caspase-8、caspase-9、cleaved-caspase-9、Bax、Bcl-2蛋白表达水平。结果 细胞免疫荧光染色鉴定结果显示分离培养的细胞为海马神经元细胞,且纯度较高。MTT测定结果显示醋酸铅最适造模浓度及时间为25 μmol·L^-1染毒24 h;PF剂量为20,40,80 μmol·L-1可显著改善海马神经元细胞活性,呈剂量依赖性。与空白组相比,模型组Cyt-C含量、凋亡率、细胞内Ca²⁺浓度显著升高(P<0.01),线粒体膜电位显著降低(P<0.01)。与模型组相比,40 μmol·L^-1 PF组和80 μmol·L^-1 PF组可降低Cyt-C含量、凋亡率、细胞内Ca²⁺浓度(P<0.05或P<0.01),升高线粒体膜电位(P<0.01),20 μmol·L^-1PF组可显著升高线粒体膜电位(P<0.05)。此外,一定剂量的PF可下调cleaved-caspase-3、cleaved-caspase-8、cleaved-caspase-9、Bax蛋白表达,上调Bcl-2蛋白表达。结论 PF可抑制醋酸铅诱导的海马神经元凋亡,可通过调控Bcl-2/Bax蛋白表达发挥神经保护作用。     

芍药苷对培养小鼠皮层神经元的保护作用

目的　探讨芍药苷是否促进培养皮层神经细胞的存活 ,并对抗兴奋性氨基酸海人藻酸 (KA)所致的神经损伤。方法　解剖分离 15d胚胎小鼠皮层神经细胞 ,接种于 2 4孔板中加药培养 ,台盼蓝染色细胞 ,相差显微镜及免疫组织细胞化学方法进行形态学观察。结果　①加入芍药苷 2 0 .8和 4 1.6mg·L- 1培养 4d增加神经细胞存活数量 ,降低死亡率。②加入KA 5 0 μmol·L- 1作用 30min ,神经元肿胀 ,失去折光性 ,核偏位 ,死亡率增高。预先加入芍药苷2 0 .8和 4 1.6mg·L- 1培养 4d ,可对抗KA所致的神经损伤。结论　芍药苷可增加神经细胞存活数量 ,降低死亡率 ,对抗KA所致的兴奋性神经损伤。     

三氯化铝对大鼠海马CA1区锥体细胞钠电流的影响

目的　为了进一步明确铝及含铝化合物对神经系统的损伤及其作用机制。方法　采用全细胞膜片钳技术研究三氯化铝 (AlCl3)对急性分离的大鼠海马CA1区神经元钠通道的影响。结果　AlCl3对钠电流有明显的抑制作用 ,且呈浓度依赖性 ,10 0 0μmol·L- 1AlCl3给药前后钠电流激活曲线Vh 分别为- (5 1.3± 6 .0 )mV和 - (4 7.5± 5 .4 )mV (P <0 .0 5 ) ,k值分别为 - (8.1± 2 .3)mV和 - (8.6± 3.2 )mV(P >0 .0 5 ) ,给药前后钠电流失活曲线Vh 分别为- (6 7.4± 5 .5 )mV和 - (71.4± 4 .4 )mV(P <0 .0 5 ) ,k值分别为 (6 .1± 1.1)mV和 (6 .8± 1.2 )mV (P >0 .0 5 )。结论　AlCl3对大鼠海马CA1区神经元钠通道有抑制作用 ,这可能是铝引起中枢神经系统损伤的机制之一     

脑缺血海马CA1区突触可塑性及白藜芦醇苷对缺血性脑损伤的保护机制

海马CA1区神经元与人类、哺乳动物的学习记忆密切相关,同时海马是脑缺血后选择性易损的脑区之一.现就脑缺血大鼠海马CA1区突触可塑性及白藜芦醇苷对缺血性脑损伤的保护机制作一综述.     

亚低温对沙土鼠海马CA1区缺血后细胞凋亡的影响

目的 探讨亚低温对沙土鼠短暂性脑缺血后海马CA1区细胞凋亡的影响。方法 阻断沙土鼠双侧颈总动脉15分钟造成前脑缺血模型。实验动物随机分为假手术组、缺血再灌注组、亚低温治疗组。用光镜观察海马CA1区的神经元死亡过程．采用原位末端标记(TUNEL)法检测凋亡的神经元。结果 脑缺血后．海马CA1区锥体神经元于再灌注后2～7天死亡,再灌注第3天神经元开始凋亡．第5天达高峰。亚低温治疗抑制了缺血后海马CA1区神经元的死亡及细胞凋亡。结论 亚低温治疗对脑缺血后的神经元具有保护作用．并可抑制神经细胞凋亡的发生。     

盐酸氟桂利嗪对缺血大鼠海马CA1区神经元持续钠电流的影响

现在认为缺血时钠通道电流的变化尤其持续钠电流的变化是造成神经元损伤的重要原因[1,2],抑制持续钠电流的增加是某些神经保护剂如riluzole等缺血脑保护作用的重要机制[3].盐酸氟桂利嗪的药理作用比较广泛,其对钠通道的阻滞作用日益受到重视.本实验通过观察其对缺血大鼠海马CA1区神经元持续钠电流的影响,探讨其脑保护的机制.     

Blockade of paeoniflorin on sodium current in mouse hippocampal CA_1 neurons

AIM: To study the blockade of paeoniflorin (Pae) on I_(Na) in the acutely isolated hippocampus neurons of mice. METHODS: The whole-cell patch clamp technique was used. RESULTS: Pae inhibited I_(Na) in frequency-dependent and concentration-dependent manners, with an IC_(50) of 271μmol/L. Pae 0.3 mmol/L shifted the activation potential of the maximal I_(Na) from -40 mV to -30 mV, shifted the steady-state activation and inactivation curves toward more positive and negative potentials by 10.8 mV, and 18.2 mV, respectively, and postponed the recovery of I_(Na) inactivation state from (4.2±0.7) ms to (9.8±1.2) ms. CONCLUSION: Pae inhibited I_(Na) in mouse hippocampus neurons.     

苄普地尔抑制大鼠海马CA1区锥体细胞钠电流(英文)

目的:研究苄普地尔对大鼠海马CA1区锥体细胞钠电流的影响。方法:膜片箝全细胞记录技术。结果:苄普地尔显著降低大鼠海马CA1区锥体细胞钠电流,作用呈时间及浓度依赖关系。苄普地尔10μmol·L~(-1)的半阻断时间约为10min。IC_(50)为2.6(2.3-2.9)μmol·L~(-1)。苄普地尔10μmol·L~(-1)右移最大电流的激活电位10mV,左移半失活膜电位18mV,表明其电压依赖地影响钠通道的激活和失活过程。结论:苄普地尔阻断大鼠海马CA1区锥体细胞钠电流,可能是其抗脑缺血机制之一。     

苄普地尔抑制大鼠海马CA1区锥体细胞钠电流

AIM: To study the effects of bepridil on sodium current in rat hippocampal neurons. METHODS: All experiments were performed on acutely isolated hippocampal pyramidal neurons by means of whole-cell patch-clamp techniques. Recording media contained ion channel blockers to allow the selective activation of voltage-dependent sodium currents. RESULTS: Bepridil reduced the amplitudes of sodium current in time- and concentration-dependent manners. The half-blocking time was about 10 min in bepridil 10 micromol.L-1, and IC50 was 2.6 (2.3-2.9) micromol.L-1. Bepridil 10 micromol.L-1 shifted the maximal activation of sodium current from -50 mV to -40 mV, and the characteristic voltage of inactivation from -71 mV to -89 mV without changing the slope factor. CONCLUSION: Bepridil blocked voltage-dependent sodium current of hippocampal CA1 neurons and might have therapeutic actions for ischemia-induced brain damage.     

芍药苷对小鼠背根神经节TTX-S钠电流的影响

目的 本文通过观察芍药苷（Paeoniflorin,Pae）对小鼠背根神经节（DRG）细胞电压门控河豚毒素敏感型（TTX-S）钠电流的影响,探讨芍药苷的镇痛机制。方法 应用全细胞膜片钳技术在急性分离背根神经节细胞上记录河豚毒素敏感型钠电流。结果 芍药苷浓度依赖地抑制河豚毒素敏感型钠电流,其半抑制浓度（IC₅₀）为1 224.1 mmol·L^-1。芍药苷1 mmol·L^-1使河豚毒素敏感型钠通道的失活曲线向超极化方向转移约7.1 mV,并且延迟失活后通道的恢复,但对激活曲线没有影响。结论 芍药苷可能通过抑制河豚毒素敏感型钠通道,改变钠通道的动力学特征,从而发挥其镇痛作用。     

Effects of hydrogen peroxide on sodium current in acutely isolated rat hippocampal CA1 neurons

The effects of hydrogen peroxide (H2O2) on sodium currents (Na+ currents) in freshly dissociated rat hippocampal neurons were studied using the whole-cell patch-clamp techniques. H2O2 caused a reversible increase of the voltage-activated Na+ currents in a concentration- and voltage-dependent manner. The half-increasing concentration (EC50) of H2O2 on Na+ currents was 10.79 microM. In addition, 10 microM H2O2 shifted the steady-state inactivation curve of Na+ currents toward positive potential (control Vh = -64.58 +/- 1.22 mV, H2O2 Vh = -53.55 +/- 0.94 mV, n = 10, P < 0.01 without changing the slope factor). However, the steady-state activation curve was not affected. These results indicated that H2O2 could increase the amplitudes of Na+ currents and change the inactivation properties of Na+ channels even in very low concentration.     

Attenuated effect of tungsten carbide nanoparticles on voltage-gated sodium current of hippocampal CA1 pyramidal neurons

Nanomaterials and relevant products are now being widely used in the world, and their safety becomes a great concern for the general public. Tungsten carbide nanoparticles (nano-WC) are widely used in metallurgy, aeronautics and astronautics, however our knowledge regarding the influence of nano-WC on neurons is still lacking. The aim of this study was to investigate the impact of nano-WC on tetrodotoxin (TTX)-sensitive voltage-activated sodium current (I_Na) of hippocampal CA1 pyramidal neurons. Results showed that acute exposure of nano-WC attenuated the peak amplitudes of I_Na in a concentration-dependent manner. The minimal effective concentration was 10^?5 g/ml. The exposure of nano-WC significantly decreased current amplitudes of the current–voltage curves of I_Na from ?50 to +50 mV, shifted the steady-state activation and inactivation curves of I_Na negatively and delayed the recovery of I_Na from inactivation state. After exposure to nano-WC, the peak amplitudes, overshoots and the V-thresholds of action potentials (APs) were markedly reduced. These results suggested that exposure of nano-WC could influence some characteristics of APs evoked from the hippocampal CA1 neurons by modifying the kinetics of voltage-gated sodium channels (VGSCs).     

Enhancement of sodium metabisulfite on sodium currents in acutely isolated rat hippocampal CA1 neurons

The effect of sodium metabisulfite (SMB) on voltage-gated sodium channel currents (I(Na)) was examined in freshly isolated rat hippocampal CA1 neurons using whole-cell patch-clamp technique under voltage-clamp conditions. SMB irreversibly enhanced I(Na) in a concentration-dependent manner, shifted the inactivation curve to more positive potential, without affecting the current activation curve. In addition, SMB increased the time to peak and the inactivation time constant of I(Na). Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) could all partly inhibit the effect of SMB on the sodium current. These results suggested that SMB have neuronal toxicity by increasing the excitability of neurons and its mechanism might involve the oxidative damage on ion channels.     

Action potential changes associated with the inhibitory effects on voltage-gated sodium current of hippocampal CA1 neurons by silver nanoparticles

Nano-sized materials are now being used in medicine, biotechnology, energy, and environmental technology. Although a wide and growing number of applications for nanomaterials exist, there are limited studies available on toxicity of nanoparticles for their human risk and environmental assessment. The aim of this study was to investigate the effects of silver nanoparticles (nano-Ag) on voltage-activated sodium currents in hippocampal CA1 neurons. Nano-Ag was tested at increasing concentrations (10⁻⁶, 5 × 10⁻⁶, 10⁻⁵ g/ml). The research results showed that only nano-Ag (10⁻⁵ g/ml) reduced the amplitude of voltage-gated sodium current (I_Na). The nano-Ag particles produced a hyperpolarizing shift in the activation–voltage curve of I_Na and also delayed the recovery of I_Na from inactivation. Action potential properties and the pattern of repetitive firing were examined using whole cell current-clamp recordings. Peak amplitude and overshoot of the evoked single action potential were decreased and half-width was increased in the present of the 10⁻⁵ g/ml nano-Ag solution, and the firing rate of repetitive firing had no change. The results suggest that nano-Ag may alter the action potential of hippocampal CA1 neurons by depressing voltage-gated sodium current.     

Effects of aluminum chloride on sodium current, transient outward potassium current and delayed rectifier potassium current in acutely isolated rat hippocampal CA1 neurons.

The effects of aluminum chloride (AlCl3) on sodium current (INa), the transient outward potassium (IA) and delayed rectifier potassium currents (IK) in hippocampal CA1 neurons of rats were studied using the whole cell patch-clamp technique. AlCl3 decreased INa, IA, and IK in a partly reversible, dose and voltage-dependent manner. AlCl3 prolonged the time to peak of INa, and increased the inactivation time constants of INa and IA . In addition, 1000 microM AlCl3 shifted the voltage dependence of steady-state activation of INa, IA and IK toward positive potential, and the voltage dependence of steady-state inactivation of INa, IA toward negative potential. These results imply that AlCl3 could affect the activation and inactivation courses of sodium current and potassium current of rat hippocampal CA1 neurons, which may contribute to damage of the central nervous system by aluminum.     

Nano-CuO inhibited voltage-gated sodium current of hippocampal CA1 neurons via reactive oxygen species but independent from G-proteins pathway

The aim of this study was to investigate the effects of nano-CuO on voltage-gated sodium current (I(Na) ) in hippocampal CA1 neurons. The results suggested that nano-CuO inhibited amplitudes of I(Na) currents and prolonged peak rise time of action potential (AP). The responses to nano-CuO were inhibited by reactive oxygen species (ROS) scavenger. However, the G-proteins inhibitor did not block the effects of nano-CuO. The effects of nano-CuO were mediated through activation of ROS-I(Na) -AP signaling cascades and independent from G-proteins pathway.