钙激活钾通道在钙离子致神经细胞损伤中的作用

采用膜片钳单通道记录方法,观察原代培养新生ＳＤ大鼠皮层神经元的钙激活钾通道（ＫＣａ）特征及胞内不同游离钙水平对通道开放动力学的调节。结果显示：培养ＳＤ大鼠皮层神经元的ＫＣａ以大电导活动占优势,胞内游离钙为１０－８ｍｏｌ／Ｌ时,通道几乎不开放,在１０－６ｍｏｌ／Ｌ时达最大激活。由此表明神经元上ＫＣａ通道开放概率明显依赖于胞浆中钙离子和膜电位,ＫＣａ对胞内钙离子浓度变化极为敏感。钾通道的开放剂可能有一定的神经细胞保护作用。     

钙离子致神经细胞损伤中钙激活钾通道的应用研究

目的:采用膜片钳单通道记录法,对新生SD大鼠的皮层神经元中,钙激活钾通道(KCa)特征,及胞内不同游离钙水平,开放动力学的调节。结果:培养SD大鼠皮层神经元中,KCa以大电导活动占优势,胞内游离钙为10-8 mol/L时,通道几乎不开放,在10-6 mol/L时达最大激活。结论:神经元上KCa通道开放概率,依赖于胞浆中钙离子膜电位,KCa对胞内钙离子浓度敏感。钾通道的开放剂,有一定神经细胞保护作用。     

丹参酮ⅡA磺酸钠对原代培养猪冠脉平滑肌ATP敏感钾通道,钙？…

目的：探讨丹参酮ⅡＡ磺酸钠（ＤＳ－２０１）对原代培养猪冠脉平滑肌上ＡＴＰ敏感的钾通道（ＫＡＴＰ）、钙激活钾通道（ＫＣａ）的作用。方法：采用膜片钳通道电流记录技术进行定量研究。结果：ＫＡＴＰ（３３．１５ｐＳ）可被３０μｍｏｌ／Ｌ优降特异性阻断，而ＫＣａ（２４６．５３ｐＳ）则表现出明显的钙离子依赖性和ＴＥＡ阻断作用等特点。内面向外式膜片下，浴液中加入ＤＳ－２０１可激活ＫＡＴＰ及Ｃａ。膜电位为＋５０ｍＶ     

低密度脂蛋白对贮脂细胞内钙离子浓度的影响

研究低密度脂蛋白（ＬＤＬ）对大鼠肝脏贮脂细胞（ＦＳＣ）胞内钙离子浓度的影响及钙拮抗剂对其的干预作用。采用Ｆｕｒａ－２／ＡＭ标记法检测不同浓度ＬＤＬ（１０、２５、５０、１００、２００、５００μｇ／ｍｌ）对ＦＳＣ胞内Ｃａ＾２＋浓度峰值的主在细胞外液含钙或不含钙时，１００μｇ／ｍｌＬＤＬ剂量组对ＦＳＣ胞内Ｃａ＾２＋浓度的影响，同时测定钙拮抗剂尼卡地平和维拉帕米对ＬＤＬ引起增钙的拮抗作用，结果：ＬＤＬ能     

黄连素片对钙离子通道的拮抗作用

本研究以药理学的方法检测了黄连素片对Ｃａ＾２＋通道的拮抗作用。结果表明黄连素片的水溶液能明显抑制Ｃａ＾２＋的内流，拮抗Ｌ型钙通道促进剂Ｂａｙ ｋ８６４４对钙通道的激活，从而降低ＳＤ大鼠胸主动脉的收缩性，４０μｇ／ｍｌ浓度的黄连素片对Ｃａ＾２＋通道的抑制作用与１０＾－８ｍｏｌ／Ｌ浓度的尼群地平相似。同时用Ｂａｙ ｋ ８６４４使ＳＤ大鼠胸主动脉收缩后，黄连素片能以剂量依赖方式引发收缩动脉的自发性舒张。     

激素与生长因子在调节成骨样细胞增殖中的作用

细胞的增殖分化受多种激素和生长因子的正负调控，内环境对其也有深刻和影响。在成骨样细胞的研究中药得下列结果：１对细胞增殖的影响：ＩＧＦ－１（１－＾８ｍｏｌ／Ｌ）或ＥＧＦ（１０ｎｇ／ｍＬ）可促进细胞生长，＾３ＨＴｄＲ参入及Ｓ期细胞的百分率，ＴＮＦａ（１０－＾８ｍｏｌ／Ｌ）则可下调Ｓ期细胞以及Ｃ－ｍｙｃ，Ｃ－ｋｉ－ｒａｓ的基因表达。２对爱体数量及Ｋ＾＋通道的影响：ＰＨＴ（１０－＾８ｍｏｌ／Ｌ）可上调ＥＧ     

G蛋白对血管紧张素Ⅱ抑制ECV304钙激活通道的调节效应

目的 探讨血管紧张素Ⅱ（ＡⅡ）对人脐静脉内皮细胞株ＥＣＶ３０４大电导钙激活钾通道（ＢＫＣａ）的影响及Ｇ蛋白在此过程中的作用。方法 用细胞贴附式膜片箝技术记录ＢＫＣａ的活动电流。结果 １０＾－７ｍｏｌ／ＬＡⅡ可抑制ＥＣＶ３０４细胞膜上ＢＫＣａ的活动,表现为电流幅值下降,开放概率减小,通道开放时间缩短,关闭时间延长;Ｇ蛋白稳定激动剂ＧＴＰγＳ可对抗ＡⅡ的抑制效应,Ｇ蛋白稳定抑制剂ＧＤＰβＳ则增强ＡⅡ的     

去窦弓神经对大鼠离体胸主动脉松缩功能的影响

作比较了去窦弓神经（ＳＡＤ）和假手术大鼠主动脉对多种激动剂和Ａｃｈ的收缩和松弛作用。发现ＳＡＤ使内皮完整的胸主动脉对ＮＥ３×１０＾－７～１０＾－５ｍｏｌ／Ｌ的收缩反应和Ａｃｈ １０＾－９ｍｏｌ／Ｌ的松弛反应明显增强，可能与血管反应增敏有关；但ＳＡＤ并不显改变胸主动脉对其他激动剂（ＰＥ，ＳＴ５８７，Ｂ－ＨＴ９２０，５－ＨＴ）的收缩反应和对Ａｃｈ １０＾－８～１０＾０４ｍｏｌ／Ｌ的松弛反应。     

酮替芬对新生大鼠心肌细胞内游离钙的影响

观察了酮替芬（Ｋｅｔ）对新生鼠心肌细胞内游离钙的影响,以酶法制备新生大鼠心肌细胞悬液,用荧光探针Ｆｕｒａ－２／ＡＭ检测心肌细胞内游离钙浓度的变化。结果表明：Ｋｅｔ对静息状态下「Ｃａ＾２＋」ｉ无影响,Ｋｅｔ（１０￣５００μｍｏｌ／Ｌ）剂量依赖性抑制高钾去经及ＮＥ所致的「Ｃａ＾２＋」ｉ升高。提示：Ｋｅｔ对心肌细胞膜下坟依赖性钙通道有抑制作用,也可能抑制受体操纵型钙通道。     

胚鼠大脑皮质神经元原代培养中NMDA诱导c—fos mRNA表达

为了进一步研究对神经元的早期保护，本实验观察Ｎ－甲基－Ｄ－天门冬氨酸（ＮＭＤＡ）在胚鼠大脑皮层神经元原代培养诱导ｃ－ｆｏｓ基因表达特点。结果显示：ＮＭＤＡ可诱导快速、短暂的ｃ－ｆｏｓ基因表达，并呈剂量、时间依赖关系；ｃ－ｆｏｓ ｍＲＮＡ表达可被ＮＭＤＡ竞争性或非竞争性受体拮抗剂Ａｐ－５（５０μｍｏｌ／Ｌ）ＭＫ－８０１（１０μｍｏｌ／Ｌ）完全阻断，Ｍｇ＾２＋（２ｍｍｏｌ／Ｌ）可部分阻滞，异搏定、尼凡     

Involvement of Ca^2＋-activated K^＋Channels in Receptor-Regulated Sperm Motility in Rats

Ion fluxes have been implicated in sperm functions.A pivotal role of Ca2 hasbeen observed in variousreproductive events including sperm capacitation,acrosomereaction[1～ 3] ,sperm activation[4～ 5] and sperm motility[6～ 8] .The importance of Ca2 in-f…     

巴曲酶对原代培养的大鼠皮层神经元钙激活钾通道的作用研究

目的观察巴曲酶对原代培养新生SD大鼠皮层神经元上钙激活钾通道(Kca)作用。方法采用细胞贴附和内面向外两种膜片钳单通道记录技术检测巴曲酶对Kca作用。结果在钙浴液内,细胞贴附式膜片上,钳制膜电位+30mV,加入不同浓度巴曲酶0.15mmol/L、0.25mmol/L、0.50mmol/L、0.75mmol/L、1.0mmol/L,通道开放概率由0.005分别增加为0.013±0.002、0.082±0.011、0.131±0.012、0.211±0.010、0.062±0.009(P<0.01),在0.75mmol/L以内表现出浓度依赖性。在无钙浴液内,细胞贴附式膜片上,钳制膜电位+50mV,随巴曲酶浓度增加为0.15mmol/L、0.40mmol/L、0.60mmol/L、1.0mmol/L时,通道开放概率由0.005分别增加为0.013±0.001、0.112±0.007、0.193±0.010、0.301±0.009(P<0.05)。6例内面向外式膜片上,钳制膜电位+40mV,分别加入巴曲酶0mmol/L、0.25mmol/L、0.50mmol/L3min后,通道开放概率分别为0.012±0.007、0.011±0.009、0.013±0.008(P>0.05),巴曲酶在胞内Kca开放概率,平均开放/关闭时间,电流幅值均无明显变化。结论巴曲酶通过影响胞内游离钙水平间接调节Kca,可能对神经元有直接保护作用。     

马桑内酯对大鼠海马锥体神经元钙激活钾通道的影响

目的　了解致痫剂马桑内酯 (CL)对培养的大鼠海马锥体神经元细胞膜钙激活钾通道 (KCa)的调节作用及癫痫的发病机理。方法　采用膜片钳单通道电流记录技术进行定量研究。结果　 1在内面向外式膜片下 ,KCa(12 0 .34± 2 5 .12 ) p S表现出钙离子浓度依赖性 (n=6 )、电压依赖性 (n=17)和四乙基胺 (TEA)阻断特点 ;2在细胞贴附式膜片下 ,浴液中加入 CL 可明显激活 KCa(P<0 .0 1) ;3在对称性高钾溶液中 ,使浴液 [Ca2 + ]i 为 10 - 8m ol/L,维持神经元膜电位为 2 0 m V,当 CL 为 0 μl/ m l和 1.0 μl/ m l时 ,可分别使 KCa开放概率从 0 .0 2 5增加到 0 .5 5 3(P<0 .0 1) ,通道活动的平均开放时间 (ms)从 1.875± 0 .4 12增加到 6 .82 9± 0 .136 ,平均关闭时间 (m s)从 179.342±13.831降低到 6 .4 12± 1.383(n=2 5 ,P<0 .0 1)。结论　在 CL 诱导的癫痫发病中 ,钙激活钾通道活化可能起重要的负反馈调节作用。     

Effects of L-THP on Ca2+ Overload of Cultured Rat Cardiomyocytes during Hypoxia and Reoxygenation

Ca2 overloadisoneoftheimportantpathophys-iologicalcharactersofcardiomyocyteinjuryfOllowinghypoxia--reoxygenation.TrlggeredactivitycausedbyCa2 overloadisthemaincauseofreperfusion--arryth-mias[l].L--tetrahydropalmatine(L--THP),alsonamedrotundium,isabiologica1alkaliofcorydalisYanhusuo,aherbalCa' antagonistwhichhasbeenwidelyusedintreatingarrythmias['].Herewedevel-opedacellmodelofhypoxiaandreoxygenationwithculturedratcardiomyocytes,whichwassimilartothemodelofischemia--reperfusioninjuryoftheheart…     

Lead Can Inhibit NMDA^—,K^＋—,QA／KA—Induced Increases in Intracellular Free Ca^2＋ in Cultured at Hippocampal Neurons

Objective To examine the effects of Pb2+ on N-methyl-D-aspartate (NMDA)-, K+- and quisqualate(QA)/kainite(KA)-induced increases in intracellular free calcium concentration ([Ca2+]i) in cultured fetal rat hippocampal neurons in order to explain the cognitive and learning deficits produced by this heavy metal. Methods Laser scanning confocal microscopy was used. Results The results clearly demonstrated that adding Pb2+ before or after NMDA/glycine stimulation selectively inhibited the stimulated increases in [Ca2+]i in a concentration-dependent manner. In contrast, Pb2+ treatment did not markedly affect increases in [Ca2+]i induced by an admixture of QA and KA. The minimal inhibitory effect of Pb2+ occurred at 1 μ mol/L, and more than seventy percent abolition of the NMDA-stimulated increase in [Ca2+]iwas observed at 100 μmol/L Pb2+. Evaluation of pb2+-induced increase in [Ca2+]i response to elevating extracellular concentrations of NMDA, glycine or calcium revealed that Pb2+ was a noncompetitive antagonist of both NMDA and glycine, and a competitive antagonist of Ca2+ at NMDA receptor channels. In addition, Pb2+ inhibited depolarization-evoked increases in [Ca2+]i mediated by K+ stimulation (30 μmol/L), indicating that Pb2+ also depressed the voltage-dependent calcium channels. Also, the results showed that Pb2+ appeared to be able to elevate the resting levels of [Ca2+]i in cultured neurons, implying a reason for pb2+-enhanced spontaneous release of several neurotransmitters reported in several previous studies. Conclusion Lead can inhibit NMDA-, K+-, QA/KA-inducod increases in intracellular [Ca2+]i in cultured hippocampal neurons.     

1-(2, 6-二甲基苯氧基)-2-(3, 4-二甲氧基苯乙氨基) 丙烷盐酸盐对培养的乳鼠心肌细胞[Ca2+]i的影响

采用 Fura- 2 / AM显微荧光测钙技术 ,检测培养新生大鼠单个心肌细胞内游离钙的浓度 ,并观察 1- (2 ,6 -二甲基苯氧基 ) - 2 - (3,4-二甲氧基苯乙氨基 )丙烷盐酸盐 (DDPH)对不同刺激〔去氧肾上腺素 ,高 K ,血管紧张素 (Ang II)〕所致心肌细胞钙超载的影响。结果表明 :1在含钙、无钙标准台氏液 ,DDPH 10 - 4 m ol· L- 1 对去氧肾上腺素(Phe) 10 - 4 mol· L- 1 所致钙增高有显著抑制作用。 2 DDPH 10 - 4 m ol· L- 1 对高 K 5 0 m mol· L- 1 引起的 [Ca2 ]i增高有一定抑制作用 ,对 Ang 10 - 4 mol· L- 1 引起的 [Ca2 ]i增高有部分拮抗作用。提示 :DDPH可拮抗 α1 受体调控的 Ca2 通道 ,对钙库钙释放也有抑制作用 ,对电压依赖性钙通道有一定调控作用     

NO-cGMP通路对下丘脑钙激活钾通道的调控研究

目的研究一氧化氮（ＮＯ）对ＳＤ乳鼠下丘脑神经元钙激活钾（ＫＣａ）通道的作用及其机制。方法采用内面向外 式及细胞贴附式膜片钳技术比较浴槽液中加入１００μmol/L硝普钠（ＳＮＰ）前后动物下丘及神经元ＫＣａ通道动力学 的改变。结果细胞贴附式时浴槽液中加入１００μmol/L ＳＮＰ,通道开放概率由（７．３±１．５）％升高至（４０．２±６．５）％,开放时 间由（７．１２±１．４１） ｍｓ增大至（１５．３４±３．４５） ｍｓ,开放频率由（１１．３±３．５）Ｈz升高为（２６．６±４．２） Ｈz（ｎ＝１０, Ｐ＜０．０５）。结论 ＮＯ－cＧＭＰ通路可显著提高通道的开放概率,这种增强作用是通过延长通道开放时间及增加开放频率实现的,它的 病理或生理作用还有待于进一步研究。     

氯胺酮对大鼠心肌细胞钙离子移动的影响

目的研究不同浓度氯胺酮对KCl诱发的大鼠心肌细胞钙离子移动的影响，探讨其对心肌收缩力的作用。方法用Fluo-3AM钙荧光指示剂染色急性分离的大鼠心肌细胞，在激光共聚焦显微镜下动态测定用药前和使用浓度为1×10     

Flunarizine inhibits sensory neuron excitability by blocking voltage-gated Na+ and Ca2+ currents in trigeminal ganglion neurons

Background  Although flunarizine has been widely used for migraine prophylaxis with clear success, the mechanisms of its actions in migraine prophylaxis are not completely understood. The aim of this study was to investigate the effects of flunarizine on tetrodotoxin-resistant Na⁺ channels and high-voltage activated Ca²⁺ channels of acutely isolated mouse trigeminal ganglion neurons.

Methods  Sodium currents and calcium currents in trigeminal ganglion neurons were monitored using whole-cell patch-clamp recordings. Paired Student’s t test was used as appropriate to evaluate the statistical significance of differences between two group means.

Results  Both tetrodotoxin-resistant sodium currents and high-voltage activated calcium currents were blocked by flunarizine in a concentration-dependent manner with the concentration producing half-maximal current block values of 2.89 μmol/L and 2.73 μmol/L, respectively. The steady-state inactivation curves of tetrodotoxin-resistant sodium currents and high-voltage activated calcium currents were shifted towards more hyperpolarizing potentials after exposure to flunarizine. Furthermore, the actions of flunarizine in blocking tetrodotoxin-resistant sodium currents and high-voltage activated calcium currents were use-dependent, with effects enhanced at higher rates of channel activation.

Conclusion  Blockades of these currents might help explain the peripheral mechanism underlying the preventive effect of flunarizine on migraine attacks.