Action Mechanism Research of Lanthanons to Slow Vacuolar Ion Channels in Raphanus Satirus L.(Xinlimei) Radish by Patch-Clamp

We used whole-vacuolar patch-clamp recording mode to study the action mechanism of La3+ to Slow Vacuolar (SV) channels for the first time. We recorded SV channel currents of Xinlimei (Raphanus satirus L.) vacuolars. The minimum activation potentials of voltage-dependent SV channels tied in 25+/-5 mV. The increase in cytoplasmic Ca2+ led to enhancement of SV-type currents. It was found that the threshold potential of activation shifted towards more depolarized values whenever cytoplasmic Ca2+ was increased. When 10(-10) mol/L free La3+ was added to the bath, SV-type current was suppressed by 60 similar to 75%. These data showed La3+ reduced ion permeabilities of Xinlimei root vacuolar membrane.

Study of Oligonucleotide Fixation on Bilayer Lipid Membranes by Patch-clamp Pipette Support

One kind of novel BLMs was fabricated by patch-clamp pipette technology characterized in considerably sensitive to changes of electrochemical parameters.Detectiye currents and voltage presented linear relationship when BLMs was formed and it could be confirmed by Gramicidin method.Ion current was increased by dihexyl (C_ (12)) modified ssDNA fixed on the BLMs and also indicated linear relationship to ssDNA's concentration due to the interaction of (C_ 12)-ssDNA and BLMs.Further more,the regression equations were different from BLMs fixed with ssDNA probe and a blank control BLM in the same experimental conditions.The ssDNA probe was successfully fixed on patch-clamp pipette supported-BLMs.Based on our studies,a biosensor with reactive element of patch-clamp pipette-supported BLMs has been established.

A patch-clamp study on human sperm Cl^- channel reassembled into giant liposome

Aim: To record the single-channel currents and characterize the electrophysiological properties of the Cl^- channels inhuman sperm membrane. Methods: The membrane proteins extracted from the human sperm were reassembled intoliposome bilayer, and the liposomes were fused into giant liposomes with a diameter more than 10μm by dehydration-rehydration procedure. The giant liposomes were used to study the Cl^- channel activities by patch-clamp technique.Results: By patch clamping the giant liposome in an asymmetric NMDG (N-methyl-D-glucamine)-Cl (bath 100//pipette 200 mmol/L) solution system, three kinds of single-channel events with unit conductances of (74.1 ± 8.3) pS,(117.0±5.7) pS and (144.7±4.5) pS, respectively, were detected. Their activities were voltage-dependent and allwere blocked by SITS (4-acetamido-4'-isothiocyanato-stilbene-2', 2'-disulfonic acid) in a concentration-dependentmanner. By constructing the open and close dwell time distribution histograms and then fitting them with exponentialfunction, two time constants were obtained in both the open and the close states. The burst activity and conductancesubstate of the channels were observed. Conclusion; There exist three kinds of Cl^- channels with different conduc-tance in human sperm membrane at least. (Asian J Androl 2001 Sep; 3: 185 - 191)

The Reconstructing of Low Signal-noise Ratio Single Ion Channel Signal from Patch-clamp Recordings Sampled in the Colored Background Noise

The single ion channel signal is an ionic current that can be recorded by the patch clamp technique. Hidden Markov model (HMM) algorithm has been used to convert the low signal noise ratio (SNR) noisy recording into an idealized quantal one in the case of white background noise. The traditional HMM algorithm is extended and adapted to the colored background noise. A new algorithm called EHMM (Extended HMM) algorithm is proposed, and mainly validated by simulation. Results show that it’s effective.

马钱子碱抑制豚鼠心室肌细胞钠电流的作用研究

目的本研究旨在分析马钱子碱(brucine)对分离的单个豚鼠心室肌细胞钠电流(INa+)的作用,并探索其抗心律失常的可能机制。方法共选取24只健康的成年豚鼠作为实验对象,雌雄不拘,随机分为4组,每组6只:第1组是未接受任何处理的对照组,之后通过微量加样器使培养皿中brucine药物的终浓度分别达到3μmol/L、10μmol/L、30μmol/L。采用急性酶解法分离获得单个豚鼠心室肌细胞,通过全细胞膜片钳技术测量离子通道电流,以检测不同浓度的brucine对豚鼠心室肌细胞INa+的影响。结果正常的对照组没有明显的INa+电流峰值的变化,而brucine 3μmol/L组给药前后基本不影响INa+电流峰值,当brucine的浓度增加到10μmol/L时,给药前后INa+电流峰值显著下降(P<0.05),在30μmol/L组给药前后INa+电流峰值大幅度减少(P<0.01),并且这种抑制作用呈浓度依赖性。正常对照组及brucine 3μmol/L剂量组中,电流-电压曲线(Ⅰ~Ⅴ曲线)并未受到显著的影响;然而,10μmol/L、30μmol/L剂量组与对照组比较,INa+的Ⅰ~Ⅴ曲线上移,无平行移动,且曲线形状不变。结论Brucine能够通过抑制心室肌细胞钠通道电流发挥抗心律失常作用。

MicroRNA-502-3p regulates GABAergic synapse function in hippocampal neurons

Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's disease-related dementia.Our previous study identified the upregulation of microRNA-502-3p(miR-502-3p)and downregulation of GABA type A receptor subunitα-1 in Alzheimer's disease synapses.This study investigated a new molecular relationship between miR-502-3p and GABAergic synapse function.In vitro studies were perfo rmed using the mouse hippocampal neuronal cell line HT22 and miR-502-3p agomiRs and antagomiRs.In silico analysis identified multiple binding sites of miR-502-3p at GABA type A receptor subunitα-1 mRNA.Luciferase assay confirmed that miR-502-3p targets the GABA type A receptor subunitα-1 gene and suppresses the luciferase activity.Furthermore,quantitative reve rse transcription-polymerase chain reaction,miRNA in situ hybridization,immunoblotting,and immunostaining analysis confirmed that overexpression of miR-502-3p reduced the GABA type A receptor subunitα-1 level,while suppression of miR-502-3p increased the level of GABA type A receptor subunitα-1 protein.Notably,as a result of the overexpression of miR-502-3p,cell viability was found to be reduced,and the population of necrotic cells was found to be increased.The whole cell patch-clamp analysis of human-GABA receptor A-α1/β3/γ2L human embryonic kidney(HEK)recombinant cell line also showed that overexpression of miR-502-3p reduced the GABA current and overall GABA function,suggesting a negative correlation between miR-502-3p levels and GABAergic synapse function.Additionally,the levels of proteins associated with Alzheimer s disease were high with miR-502-3p overexpression and reduced with miR-502-3p suppression.The present study provides insight into the molecular mechanism of regulation of GABAergic synapses by miR-502-3p.We propose that micro-RNA,in particular miR-502-3p,could be a potential therapeutic to rget to modulate GABAergic synapse function in neurological disorders,including Alzheimer's disease and Alzheimer's diseaserelated dementia.

环状RNA mmu_circ_0005019影响小鼠心肌细胞钙激活钾通道电流及动作电位

目的 探索环状RNA mmu_circ_0005019调控小电导钙激活钾(small-conductance calcium-activated potassium, SK)通道蛋白亚基SK3编码基因Kcnn3的表达,以及对小电导钙激活钾通道电流(IK,Ca)和动作电位时程(action potential duration, APD)的影响。方法 在小鼠HL-1细胞中分别构建mmu_circ_0005019过表达和干扰模型,分为过表达组(n=3)、空质粒组(n=3)、干扰1组(n=3)、干扰2组(n=3)、对照组(n=3),通过RT-qPCR、Western blot分析mmu_circ_0005019调节Kcnn3表达的分子机制,应用膜片钳技术电流钳模式记录全细胞的IK,Ca,并用电压钳模式记录APD。结果 成功构建了环状RNA mmu_circ_0005019过表达和干扰的HL-1细胞模型。过表达组的Kcnn3基因表达与空质粒组相比明显上调(P<0.05);干扰1组和干扰2组的Kcnn3基因表达与对照组相比均明显下调(P<0.05)。电生理发现过表达mmu_circ_0005019增加了HL-1细胞IK,Ca电流密度,APD显著缩短;相反,干扰mmu_circ_0005019减少了IK,Ca电流密度,APD显著延长。结论 mmu_circ_0005019可以上调小鼠HL-1细胞Kcnn3的表达水平,从而改变IK,Ca和APD,提示环状RNA mmu_circ_0005019可能在房颤发生中起到促进作用。

无镁诱导仓鼠原代皮质神经元电生理学特性

目的无镁细胞外液建立癫痫放电模型,利用全细胞膜片钳技术,检测仓鼠原代皮质神经元的电生理学特性。方法采用生后1~2 d新生叙利亚仓鼠,分离大脑皮质培养原代神经元培养至第12天,分别予有镁细胞外液(有镁组)和无镁细胞外液(无镁组)孵育3 h,3 h后均更换为正常孵育液继续培养24 h。利用全细胞膜片钳技术,电压钳模式下记录神经元兴奋性突触后电流(excitatory postsynaptic currents,EPSC),电流钳模式下记录神经元兴奋性突触后电位(excitatory postsynaptic potentials,EPSP)。结果与有镁组相比,无镁组仓鼠原代皮质神经元EPSC[(124.38±75.15)Hz vs.(33.93±22.32)Hz,P<0.001]及EPSP[(37.05±38.37)Hz vs.(5.63±9.52)Hz,P<0.01]的频率升高,且差异有统计学意义;而两组之间EPSC及EPSP的振幅、曲线下面积和半宽度的差异无统计学意义(P>0.05)。结论无镁处理后仓鼠原代皮质神经元兴奋性升高,仓鼠原代皮质神经元可用于构建癫痫细胞模型。

神经示踪染料DiI影响溃疡性结肠炎小鼠背根神经节神经元电学特性

目的:探究在神经示踪结合膜片钳全细胞记录的实验中,示踪染料DiI是否会对小鼠背根神经节(dorsal root ganglion,DRG)神经元兴奋性产生影响。方法:采用SPF级雄性C57BL/6J小鼠,经5%葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导溃疡性结肠炎(ulcerative colitis,UC)模型,在T12~L2皮节多点注射DiI逆向示踪躯体感觉神经元,分离全组织DRG并进行全细胞膜片钳记录。结果:HE染色结果显示模型诱导成功。膜片钳记录未经标记的小鼠DRG神经元,模型组小鼠膜电位兴奋性高于正常组小鼠。两组小鼠示踪后,正常示踪组和模型示踪组DiI+神经元兴奋性均低于本组DiI-神经元;与两未示踪组的神经元相比较,两示踪组的DiI-神经元兴奋性分别升高。结论:本实验结果明确了示踪剂DiI会降低DRG神经元的兴奋性,提示相关实验设计中应注意示踪剂的应用对神经元兴奋性的影响,以保证实验结果的可靠性。

Study of transmembrane La^(3+) movement in rat ventricular myocytes by the patch-clamp technique

We have studied transmembrane La3+ movement in rat ventricular myocytes for the first time by using the whole-cell patch-clamp recording mode. La3+ (0.01-5.0 mmol/L) could not bring out inward currents through the L-type calcium channel in rat ventricular myocytes, while it could enter the cells by the same way carried by 1μmo1/L ionomycin. When the outward Na+ concentration gradient is formed, La3+ can enter the cells via Na-Ca exchange, and the exchange currents increase with the increase of external La3+ concentrations. But compared with Na-Ca exchange currents in the same concentration, the former is only 14%-38% of the latter. The patch-clamp experiment indicates that La3+ normally can not enter ventricular myocytes through L-type calcium channel, but it can enter the cells via Na-Ca exchange.

冬凌草甲素对海马CA1星形胶质细胞P2X7受体电流的影响

目的:探索冬凌草甲素是否对海马CA1星形胶质细胞P2X7受体电流有影响。方法:采用Autodock软件对冬凌草甲素与P2X7蛋白进行分子对接;采用全细胞膜片钳记录冬凌草甲素对海马CA1星形胶质细胞P2X7受体激动剂Bz-ATP激发电流的影响。结果:冬凌草甲素与P2X7蛋白的结合能为-5.86 kcal/mol,可与P2X7蛋白的Lys592残基形成氢键,与Tyr550残基形成疏水作用;Bz-ATP能激发海马CA1区星形胶质细胞的电流反应,且1000μmol/L Bz-ATP激发的电流反应较强;10μmol/L冬凌草甲素溶液孵育1 h后,海马CA1区星形胶质细胞对谷氨酸能受体激动剂NMDA和AMPA溶液的电流反应无明显变化;对Bz-ATP的电流反应降低,差异具有统计学意义(P<0.05)。结论:冬凌草甲素可与P2X7蛋白对接形成稳定的复合物,具有较好的亲和力;冬凌草甲素可抑制海马CA1星形胶质细胞P2X7受体电流。

抗肿瘤药物开发中体外心脏的安全性风险评估

背景:酪氨酸激酶抑制剂以及其他种类的小分子癌类药物会导致严重的心脏毒性。目的:通过观察抗肿瘤药物在兔体外心脏心电图、心肌动作电位及相关离子通道和心肌细胞毒性的作用,对心脏安全再评价。方法:将兔进行体外心脏灌流,采用舒尼替尼(Sunitinib,0.3,3,10μmol/L),克唑替尼(Crizotinib,0.3,1,3μmol/L),多柔比星(Doxorubicin,1,30μmol/L)顺序灌流120 min,并设空白对照组进行对比,记录心电图和左心室内压。采用手动膜片钳检测3种药物对人源诱导多能干细胞分化的心肌细胞(hiPSC-CMs)动作电位及相关离子通道hERG,Nav1.5和Cav1.2通道电流的影响,采用CellTiter-Glo荧光细胞活力法检测hiPSC-CMs中ATP的水平。结果与结论:①体外心脏灌流实验结果显示:与空白对照组相比,Sunitinib和Crizotinib在≥3μmol/L浓度灌流下可减慢兔心率(P<0.01),延长QT/QTc间期(P<0.01),左心室内压有不同程度的降低。②手动膜片钳实验显示,与空白对照组相比,Sunitinib和Crizotinib在3μmol/L浓度灌流时可明显延长hiPSC-CMs动作电位时程(P<0.01),抑制hERG,Nav1.5和Cav1.2离子通道电流;并结合供试品分析,标识浓度与回收液测定浓度有不同程度的差异。③细胞活力检测结果显示,与空白对照组相比,Sunitinib(IC_(50)=4.64μmol/L),Doxorubicin(IC_(50)=4.21μmol/L)和Crizotinib(IC_(50)=2.87μmol/L)处理后hiPSC-CMs细胞内ATP水平明显降低,即细胞活力显著降低(P<0.01)。④上述结果证实,实验成功建立了抗肿瘤药物的早期心脏安全性评价方法,为后续抗肿瘤药物的开发提供良好的支持和帮助。

手动膜片钳检测盐酸罗哌卡因及其右旋异构体对HEK293细胞hERG电流的影响

目的研究比较盐酸罗哌卡因和盐酸罗哌卡因右旋异构体对高表达hERG钾通道的HEK293细胞hERG电流的影响。方法用手动膜片钳检测转染后hERG钾通道稳定表达的HEK293细胞电流,多菲莱德做阳性药,将盐酸罗哌卡因和盐酸罗哌卡因右旋异构体依次稀释成30.00、10.00、3.33、1.11、0.37μmol·L^(-1),依次作用于细胞,记录电流变化,计算抑制率。结果盐酸罗哌卡因0.37、1.11、3.33、10、30μmol·L^(-1)对电流Iherg-tail的抑制率分别为(6.12±0.30)%、(13.04±1.20)%、(19.21±0.33)%、(35.56±0.66)%、(65.37±4.17)%,IC_(50)为19.482μmol·L^(-1)(n=15)。盐酸罗哌卡因右旋异构体0.37、1.11、3.33、10.00、30.00μmol·L^(-1)对电流Iherg-tail的抑制率分别为(4.13±3.43)%、(7.34±5.60)%、(9.49±2.75)%、(16.60±0.87)%、(31.36±1.45)%,IC_(50)>30μmol·L^(-1)(n=15)。阳性对照药品多菲莱德0.00185、0.00556、0.01667、0.05000、0.15000μmol·L^(-1)对电流Iherg-tail的抑制率分别为(7.81±2.77)%、(19.67±1.88)%、(57.16±4.39)%、(89.71±3.55)%、(99.66±0.89)%、IC_(50)为0.015μmol·L^(-1)(n=15)。结论和阳性对照药品多菲莱德比较,盐酸罗哌卡因对hERG通道为弱抑制作用,盐酸罗哌卡因右旋异构体对hERG通道为无明显抑制作用。

Effects of BaCl_2 on slow vacuolar ion channels on radish by patch-clamp

Effects of BaCl2 on slow vacuolar ion channels on radish by patch-clamp YANG Pin (杨 频) & ZHANG Liping (张丽平) Institute of Molecular Science, Shanxi University, Taiyuan 030006, China Correspondence should be addressed to Yang Pin (email: yangpin@sxu.edu.cn)

Design and fabrication of a planar patch-clamp substrate using a silicon-on-insulator wafer

The planar patch-clamp technique has been applied to high throughput screening in drug discovery. The key feature of this technique is the fabrication of a planar patch-clamp substrate using appropriate materials. In this study, a planar patch-clamp substrate was designed and fabricated using a silicon-on-insulator （SOI） wafer. The access resistance and capacitance of SOl-based planar patch-clamp substrates are smaller than those of bulk silicon-based planar substrates, which will reduce the distributed RC noise.

Effect of La^(3+) on myocardiac potassium channels revealed by patch-clamp technique

The effect of La3+ on potassium channels in rat ventricular myocytes was investigated using the whole-cell patch-clamp recording mode. The Ca2+-independent voltage- activated outward K+ current was activated by the depolar- izing pulse in enzymatically isolated rat ventricular myocytes. After addition of different concentrations La3+ to the bath solution, the outward K+ current was depressed gradually. The inhibition effect was in a concentration-dependent man- ner. The phenomena of the outward K+ current, being the main repolarizing current suppressed by La3+, suggest that the effect of lanthanides on myocardial function should be exploited further.

L-and T-type Ca^(2+)channels dichotomously contribute to retinal ganglion cell injury in experimental glaucoma

Retinal ganglion cell apoptotic death is the main pathological characteristic of glaucoma,which is the leading cause of irreversible blindness.Disruption of Ca^(2+)homeostasis plays an important role in glaucoma.Voltage-gated Ca^(2+)channel blockers have been shown to improve vision in patients with glaucoma.However,whether and how voltage-gated Ca^(2+)channels are involved in retinal ganglion cell apoptotic death are largely unknown.In this study,we found that total Ca^(2+)current densities in retinal ganglion cells were reduced in a rat model of chronic ocular hypertension experimental glaucoma,as determined by whole-cell patch-clamp electrophysiological recordings.Further analysis showed that L-type Ca^(2+)currents were downregulated while T-type Ca^(2+)currents were upregulated at the later stage of glaucoma.Western blot assay and immunofluorescence experiments confirmed that expression of the Ca_(V)1.2 subunit of L-type Ca^(2+)channels was reduced and expression of the Ca_(V)3.3 subunit of T-type Ca^(2+)channels was increased in retinas of the chronic ocular hypertension model.Soluble tumor necrosis factor-α,an important inflammatory factor,inhibited the L-type Ca^(2+)current of isolated retinal ganglion cells from control rats and enhanced the T-type Ca^(2+)current.These changes were blocked by the tumor necrosis factor-αinhibitor XPro1595,indicating that both types of Ca^(2+)currents may be mediated by soluble tumor necrosis factor-α.The intracellular mitogen-activated protein kinase/extracellular signal-regulated kinase pathway and nuclear factor kappa-B signaling pathway mediate the effects of tumor necrosis factor-α.TUNEL assays revealed that mibefradil,a T-type calcium channel blocker,reduced the number of apoptotic retinal ganglion cells in the rat model of chronic ocular hypertension.These results suggest that T-type Ca^(2+)channels are involved in disrupted Ca^(2+)homeostasis and apoptosis of retinal ganglion cells in glaucoma,and application of T-type Ca^(2+)channel blockers,especially a specific CaV3.3 blocker,may be a potential strategy for the treatment of glaucoma.

神经营养因子3-壳聚糖载体诱导神经干细胞分化为神经元的亚型及其电生理特性

背景:前期研究已证实神经营养因子3-壳聚糖载体可支持神经干细胞的存活和增殖,同时可高效诱导神经干细胞向神经元方向分化。目的:观察神经营养因子3-壳聚糖载体对神经元发育进程、发育各阶段电生理特性及发育成熟神经元亚型的影响。方法:取第3代新生大鼠脊髓神经干细胞,分4组培养:空白对照组加入神经干细胞培养基,壳聚糖组加入含壳聚糖的神经干细胞培养基,NT3组加入含神经营养因子3的神经干细胞培养基,NT3-壳聚糖组加入含神经营养因子3-壳聚糖载体的神经干细胞培养基。利用免疫荧光染色观察神经干细胞发育各阶段标志物表达情况,借助全细胞膜片钳技术评价神经干细胞发育过程中电生理特性的变化情况,利用免疫荧光染色观察神经干细胞分化21 d后中间神经元的亚型。结果与结论:①Nestin、DCX、Tuj1及MAP2免疫荧光染色显示,神经营养因子3-壳聚糖载体维持了神经干细胞池的稳态,并且通过加速神经母细胞的发育进程来促进神经元发育成熟;②全细胞膜片钳记录发育过程中的细胞发现,营养因子神经营养因子3和神经营养因子3-壳聚糖在发育早期对神经干细胞膜功能以及细胞膜上离子通道的发育成熟具有一定的促进作用,但是仅有神经营养因子3-壳聚糖可将这一优势维持到发育中后期,即分化后7-14 d;③免疫荧光染色显示,神经干细胞分化21 d后,NT3-壳聚糖组成熟神经元可表达运动神经元特异性标记物HB9、V1类型中间神经元FOXP1、V2类型中间神经元特异性标记物LHX3,以及调控机械性痛觉感觉中间神经元的特异性标记物VGLUT3;④结果显示,神经营养因子3-壳聚糖载体促进了神经干细胞向神经母细胞的发育,在发育早期对细胞膜功能及细胞膜上的离子通道发育成熟具有一定的促进作用,可诱导发育成熟的神经元亚型多样化。

临床浓度的依托咪酯对脊髓腹角神经元GABA和甘氨酸电流的作用

目的:研究临床浓度依托咪酯(ET)对脊髓腹角神经元γ-氨基丁酸(GABA)诱导的电流和甘氨酸(Gly)诱导的电流的幅度及动力学指标的影响。方法:以7~14日龄的新生SD大鼠作为实验动物,将含腰骶膨大的脊髓切成厚度为300~500μm的薄片,经酶解消化后,机械吹打含腹角的切片,分离出单个神经元后进行穿孔膜片钳记录。在电压钳模式下(V H=-70 mV),分别使用GABA(0.1 mmol/L)和Gly(30.0μmol/L)在分离的脊髓腹角神经元上诱发出电流,并研究临床浓度的ET对这两种电流的峰电流、稳态电流的幅度和动力学指标的影响。结果:相当于临床浓度的3.0μmol/L的ET自身无法在分离的脊髓腹角神经元上诱发出电流。但使用3.0μmol/L的ET对记录的神经元预处理2 min后,与对照电流相比,能够增大GABA峰电流幅度和稳态电流幅度(P<0.01)。使用3.0μmol/L的ET预处理2 min后,与对照电流相比,能够增大Gly峰电流幅度和稳态电流幅度(P<0.01)。同时,3.0μmol/L的ET预处理2 min缩短了GABA电流的上升时间(RT)(P<0.01),而延长了其衰减时间(DT)(P<0.01)。使用相同浓度的ET预处理2 min后,Gly电流的RT缩短(P<0.01)而DT延长(P<0.01)。结论:临床浓度的ET对脊髓腹角神经元的GABA和Gly峰电流和稳态电流的幅度皆有增强作用,并且对GABA电流和Gly电流这两种电流的激活和失敏动力学指标皆具有差异性影响。

大蒜素对小鼠心房肌细胞多种钾电流的阻滞效应

目的 探讨大蒜素对小鼠心房肌细胞多种钾电流的作用及其机制。方法 采取双酶消化法将单个小鼠心房肌细胞分离出来,灌流法将药物作用于细胞,采用全细胞膜片钳技术,分别记录心房肌细胞的外向钾电流(I_(K,peak))、瞬时外向钾电流(I_(to))和超极化激活延迟整流钾电流(I_(KUr))。结果 钳制电压在+70 mV时,30μmol/L大蒜素可使小鼠心房肌细胞I_(K,peak)、I_(to)和I_(KUr)峰值显著降低,对I_(to)表现出抑制作用,该作用还呈现出一定的浓度依赖性和电压依赖性,半数抑制浓度(IC_(50))为(21.0±3.8)μmol/L。深入研究门控机制结果显示,I_(to)通道稳态失活曲线在大蒜素的作用下发生左移,且失活后再次激活的时间有所延迟,对于通道的关闭态失活过程影响不大,提示大蒜素主要通过抑制通道稳态失活和失活后恢复过程,减少I_(to)电流密度,同时对I_(KUr)也有阻滞作用,进而导致对总的外向电流抑制。结论 大蒜素可以直接降低小鼠心房肌细胞多种钾电流,这为进一步应用于房性心律失常提供潜在的可能。