用荧光钙离子指示剂fura—2AM检测心肌细胞内游离钙

本实验采用游离钙离子荧光指示剂fura－2AM检测大鼠离体心室肌细胞内游离钙的浓度。其结果如下；（1）KC1可以使心肌细胞内游离钙浓度升高，去掉细胞外液中钙离子，KC1的升钙作用则消失。（2）甲氧胺和咖啡因可使心肌细胞内游离钙浓度升高。二者的作用分别被哌唑嗪和普鲁卡因所对抗。提示该法切实可行。     

依脉特灵对Ca^2＋所致小鼠离体子宫平滑肌收缩的拮抗作用

本文观察到IT对小鼠离体子宫平滑肌高K~+去极化后Ca~(2+)所致的收缩有显著抑制作用。CaCl_2量效曲线IT对其呈非竞争性拮抗。在无Ca~(2+)高K~+溶液中,IT10μM抑制OXY依赖细胞内Ca~(2+)引起的收缩,而IT50μM对依赖细胞内外Ca~(2+)所致子宫肌收缩均有抑制作用。Ver对小鼠离体子宫的作用,远较IT的强。但Ver较高浓度(59nM)只抑制依赖细胞内Ca~(2+)的收缩,对依赖细胞外Ca~(2+)的收缩影响甚少。IT与Vcr拮抗ca~(2+)的作用相似。IT为Ca~(2+)拮抗剂。     

Ca~(2+)、钙拮抗剂与肝纤维化

<正> Ca~(2+)是细胞内重要的信息物质,对细胞的生理活动具有重要的调节作用。钙通道阻滞剂能够抑制细胞外液Ca~(2+)内流,使细胞内Ca~(2+)浓度降低而发挥广泛的生物学效应。它已广泛应用于临床心血管疾病的治疗,但其对肝脏疾病,特别是肝纤维化的作用正愈来愈受到人们重视。现就Ca~(2+)、钙拮抗剂及其对肝纤维化的作用作一简要综述。     

Aβ诱导PC-12细胞凋亡建立阿尔茨海默病细胞模型

目的:用β-淀粉样蛋白(Aβ_(25-35))诱导PC-12细胞凋亡以建立阿尔茨海默病细胞模型。方法:体外培养大鼠嗜铬细胞瘤PC-12细胞,以不同浓度Aβ_(25-35)诱导并于不同时间收获细胞,应用MTT法观察细胞活力,Fura-2/AM荧光分析法检测细胞内游离Ca~(2+)浓度,Hoech-st33258及碘化丙啶复染分析细胞凋亡。结果:Aβ_(25-35)作用于PC-12细胞后,细胞活力逐渐下降,并呈时间和剂量依赖性;同时细胞内Ca~(2+)浓度显著上升;不同浓度Aβ_(25-35)作用后,PC-12细胞于不同时间出现凋亡的典型形态学特征,该时间比Ca~(2+)浓度上升约晚6-12 h。结论:Aβ_(25-35)诱导PC-12细胞活力下降、细胞内Ca~(2+)浓度上升及细胞凋亡,可作为较理想的阿尔茨海默病细胞模型。     

钙离子的生理与病理作用的最新认识

一、钙离子(Ca~(2+))的生理运转和作用正常细胞内Ca~(2+)浓度为10~(-7)M)100～200nM),细胞外浓度为10~(-3)M(1000000nM)。细胞内外呈1:10,000之差,即质膜内外浓度梯度相差5,000～10,000倍,细胞内的Ca~(2+)90％聚集在线粒体和内质网上。     

维拉帕米对盐酸降低胃粘膜细胞外Ca~(2+)活度和跨粘膜电位效应的影响

应用钙离子选择微电极技术,观察了维拉帕米和异丙肾上腺素对由酸化蟾蜍胃窦粘膜引起的细胞外Ca~(2+)活度和跨粘膜电位下降效应的影响。实验结果表明,维拉帕米抑制盐酸降低细胞外Ca~(2+)活度和跨粘膜电位的效应,而异丙肾上腺素则增强细胞外Ca~(2+)活度的下降效果,但对跨粘膜电位的下降则无明显影响。结果提示,由盐酸刺激引起的胃窦粘膜细胞外Ca~(2+)活度的下降很可能是由于Ca~(2+)向细胞内转移的量增加所致。     

过表达Junctate蛋白对小鼠心肌细胞肌浆网Ca~(2+)浓度调节的影响

目的:探讨过表达junctate蛋白后,小鼠心肌细胞肌浆网上钙通道对细胞内钙离子浓度调节的影响。方法:以正常表达junctate蛋白的小鼠(wild-type mice,WT)心肌细胞为WT组,以过表达junctate蛋白的转基因小鼠(transgenic mice,TG)心肌细胞为TG组,用离子荧光测定仪测定两组小鼠心肌细胞静息状态下的钙离子浓度,后再分别测定两组小鼠在给予咖啡因及氯化钾刺激后,心肌细胞内的钙离子浓度的变化情况,并测定咖啡因引起钙瞬变后的恢复时间。结果:静息状态下,TG组心肌细胞[Ca~(2+)]i为(77.6!8.8)nmol·L-1,显著低于WT组(144.2!10.6)nmol·L-1,(P<0.01);加入咖啡因后,TG组细胞内钙瞬变幅度显著低于WT组,且TG组钙瞬变后自峰值恢复到基础水平的时间较WT组明显延长(P<0.01);加入KCl后,两组细胞内[Ca~(2+)]i均瞬间增高,TG组心肌细胞内钙瞬变幅度明显大于WT组(P<0.01)。结论:过表达junctate蛋白会影响肌浆网对细胞内钙离子浓度的调节,其机制可能是过表达junctate蛋白会导致兰尼碱受体(Ryanodine receptor,RyR)功能上调、肌浆网Ca~(2+)-ATP酶(Sarcoplasmic-endoplasmic-reticulum Ca~(2+)-ATPase,SERCA)功能下调,并使肌浆网钙库储存量减少,最终导致静息状态及去极化状态下细胞内钙离子浓度异常。     

细胞外Ca~(2+)浓度对大鼠离体黄体细胞孕酮生成的影响

用大鼠离体培养大、小黄体细胞,观察了细胞外Ca~(2+)浓度变化对大、小黄体细胞孕酮生成的影响。结果显示,用无Ca~(2+)、Mg~(2+)的KRBG液培养或增加细胞外Ca~(2+)浓度及培养液中加入EGTA时,对大、小黄体细胞孕酮生成均有影响,但对大黄休细胞的作用更为显著。这些结果一致表明,Ca~(2+)对大、小黄体细胞孕酮生成有促进作用,但在基础孕酮分泌中,大黄体细胞更明显依赖于细胞外液Ca~(2+)。     

作用于钙受体药物的研制

细胞外Ca~(2+)浓度升高时,甲状旁腺的甲状旁腺激素(PTH)分泌会减少;相反,细胞外Ca~(2+)浓度降低时,PTH分泌就会增加,很久以来业已表明甲状旁腺细胞表面可能存在感知细胞外Ca~(2+)浓度的感受器。1993年Brown等人成功地克隆出Ca受体,证明了该感受器是迄今许多低分子药物作用目标——7次膜贯通G蛋白共轭型受体。     

人参皂苷Rg_1对H_2O_2诱导的HT22细胞凋亡及胞内Ca~(2+)变化的影响

目的研究人参皂苷Rg_1对H_2O_2诱导的HT22细胞凋亡及胞内Ca~(2+)浓度变化的影响。方法以0、6.25、12.5、25、50、100μg/L人参皂苷Rg_1预处理细胞24 h,采用Ca~(2+)荧光染料探针Fluo-3/AM负载细胞1 h后,50 mmol/L H_2O_2刺激细胞,多功能酶标仪测定荧光强度,激光共聚焦显微镜实时监测[Ca~(2+)]i变化,Hoechst 33258染色检测细胞凋亡。结果 H_2O_2可诱导细胞内Ca~(2+)浓度增加(P0.01),并增加细胞凋亡率(P0.01)。不同浓度人参皂苷Rg_1可呈剂量依赖性的抑制H_2O_2诱导的HT22[Ca~(2+)]i增加(P0.01),抑制细胞凋亡(P0.01),以50μg/L的作用为最强(P0.01)。结论人参皂苷Rg_1可通过降低H_2O_2诱导的HT22细胞内Ca~(2+)水平的升高,抑制氧化应激引起的细胞凋亡。     

Effects of remifentanil on intracellular Ca2+ and its transients induced by electrical stimulation and caffeine in rat ventricular myocytes

Background Preconditioning with remifentanil confers cardioprotection. Since Ca^2＋ overload is a precipitating factor of injury, we determined the effects of remefentanil on intracellular Ca^2＋ （[Ca^2＋]i） and its transients induced by electrical stimulation and caffeine, which reflects Ca^2＋ handling by Ca^2＋ handling proteins, in rat ventricular myocytes. Methods Freshly isolated adult male Sprague-Dawley rat myocytes were loaded with Fura-2/AM and [Ca]i was determined by spectrofluorometry. Remifentanil at 0.1-1000 μg/L was administered. Ten minutes after administration, either 0.2 Hz electrical stimulation was applied or 10 mmol/L caffeine was added. The [Ca^2＋]i, and the amplitude, time resting and 50% decay （t50） of both transients induced by electrical stimulation （E[Ca^2＋]i） and caffeine （C[Ca^2＋]i） were determined. Results Remifentanil （0.1-1000.0 μg/L） decreased the [Ca^2＋]i in a dose-dependent manner. It also decreased the amplitude of both transients dose-dependently. Furthermore, it increased the time to peak and tso of both transients dose-dependently. Conclusion Remifentanil reduced the [Ca^2＋]i and suppressed the transients induced by electrical stimulation and caffeine in rat ventricular myocytes.     

Effects of Aconitine on [Ca2＋] Oscillation in Cultured Myocytes of Neonatal Rats

In order to investigate the effects of aconitine on [Ca2 ] oscillation patterns in cultured myocytes of neonatal rats, fluorescent Ca2 indicator Fluo-4 NW and laser scanning confocal micro- scope (LSCM) were used to detect the real-time changes of [Ca2 ] oscillation patterns in the cultured myocytes before and after aconitine (1.0 μmol/L) incubation or antiarrhythmic peptide (AAP) and aconitine co-incubation. The results showed under control conditions, [Ca2 ] oscillations were irregu- lar but relatively stable, occasionally accompanied by small calcium sparks. After incubation of the cultures with aconitine, high frequency [Ca2 ] oscillations emerged in both nuclear and cytoplasmic regions, whereas typical calcium sparks disappeared and the average [Ca2 ] in the cytoplasm of the cardiomyocyte did not change significantly. In AAP-treated cultures, intracellular [Ca2 ] oscillation also changed, with periodic frequency, increased amplitudes and prolonged duration of calcium sparks. These patterns were not altered significantly by subsequent aconitine incubation. The basal value of [Ca2 ] in nuclear region was higher than that in the cytoplasmic region. In the presence or absence of drugs, the [Ca2 ] oscillated synchronously in both the nuclear and cytoplasmic regions of the same cardiomyocyte. It was concluded that although oscillating strenuously at high frequency, the average [Ca2 ] in the cytoplasm of cardiomyocyte did not change significantly after aconitine incuba- tion, compared to the controls. The observations indicate that aconitine induces the changes in [Ca2 ] oscillation frequency other than the Ca2 overload.     

异丙酚对氯化钾和咖啡因诱发豚鼠耳蜗外毛细胞钙离子移动的影响

目的:评价异丙酚对氯化钾和咖啡因诱发豚鼠耳蜗外毛细胞钙离子移动的影响,探讨其对听觉外周感受器(耳蜗)的作用。方法:急性分离豚鼠耳蜗外毛细胞,选择30个活力较高的外毛细胞,随机分为3组(n=10):对照组(C组)、30μmol/L异丙酚组(P1组)和100μmol/L异丙酚组(P2组)。用Fluo-3AM钙荧光指示剂染色后,P1组和P2组分别给予30、100μmol/L异丙酚或咖啡因处理5min,然后加入氯化钾,采用激光共聚焦显微镜测定细胞内荧光强度的峰值,反映细胞内游离钙离子浓度([Ca2+]i)的变化。结果:异丙酚可抑制氯化钾诱发的[Ca2+]i增加并与浓度呈正相关,而对咖啡因诱发的[Ca2+]i增加无明显影响。结论:异丙酚可抑制豚鼠耳蜗外毛细胞Ca2+跨膜内流,降低[Ca2+]i,而对内质网功能无明显影响。     

共聚焦激光扫描显微镜技术在研究大鼠海马神经元胞内钙超载中的应用

目的 观察抑制性氨基酸牛磺酸对兴奋性氨基酸谷氨酸所致胞内钙超载的影响。方法 选择Fluo-3／ AM对培养的海马神经元进行着色后,用共聚焦激光扫描显微镜(confocal laser scanning microscope,CLSM)实时 扫描,动态显示海马神经元二维图像,以计算机相应软件对胞内钙的荧光强度变化进行分析统计。结果 在 0.5 mmol／L谷氨酸作用下,胞内钙荧光强度迅速升高(P<0.001);0.5 mmol／L谷氨酸与3 mmol／L牛磺酸共同 作用于海马神经元时,胞内钙荧光强度明显降低(P<0.001);灌流液中去除牛磺酸后,胞内钙荧光强度上升(P <0.001)。结论 抑制性氨基酸牛磺酸可抑制由兴奋性氨基酸谷氨酸所致神经元的胞内钙超载;CLSM以其独 特的优势,在高清晰度地显示海马神经元形态的同时,也可动态地观察活细胞在不同环境下胞内钙的快速变化 以及定量分析。该技术在动态观察和二维图像的高分辨率上比传统测钙方法有更大的优越性。     

Effects of nerve growth factor on intracellular free Ca2+ in oxygen/glucose-deprived cultures from cerebral cortex of fetal rats

ＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔｔｈｅｉｎｔｒａｃｅｌｕｌａｒＣａ２＋ｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｂｏｔｈｐｈｙｓｉｏｌｏｇｉｃａｌａｎｄｔｏｘｉｃｏｌｏｇｉｃａｌｐｒｏｃｅｓｓｅｓ．ＡｄｉｓｒｕｐｔｉｏｎｏｆＣａ２＋ｈｏｍｅｏｓｔａ...     

M3 受体激动剂对慢性心衰大鼠心肌ICa-L及[Ca2+]i的影响

目的 研究M3 受体激动剂胆碱( choline)对慢性心力衰竭( CHF)大鼠心肌的保护作用及可能的机制. 方法CHF大鼠Ⅱ型胶原酶消化分离单个心肌细胞,全细胞膜片钳技术记录L-型钙电流( ICa-L )变化;激光扫描共聚焦技术观测细胞内钙([Ca2+]i)变化. 结果 膜片钳实验结果显示,与CHF组比较,choline组ICa-L电流密度明显增高( n=6,P<0. 01);预敷U73122后加入choline,与choline组比较, ICa-L电流密度明显下降(n=6,P<0. 01). 共聚焦实验结果显示,与CHF组比较,choline组[ Ca2+] i 明显升高( n=80,P<0. 01);与 choline 组比较,U73122 与 choline 共同孵育组[Ca2+]i 升高幅度不明显(n=80, P<0. 01). 预先给予4-DAMP可部分逆转choline升高ICa-L及[ Ca2+] i 的作用. 结论 M3 受体对CHF大鼠的心肌保护作用可能是通过Gq/11-PLC途径开放L-型钙通道,促进Ca2+内流,使[ Ca2+] i 增加.     

慢性低氧后钙转运的变化

目的　观察大鼠慢性低氧后心肌钙转运的变化。方法　将大鼠放置于 1 0 %氧环境下 4周 ,分离正常及慢性缺氧大鼠的右心室肌细胞 ,用光谱荧光法测定电刺激和咖啡因引起的细胞内 [Ca2 ]i瞬变 ,并测定肌浆网膜上的Ca2 -ATP酶 (SERCA)和ryanodine受体 (RyR)蛋白水平。结果　低氧后电刺激和咖啡因引起的细胞内 [Ca2 ]i瞬变的幅度降低且时程延长 ,RyR水平无明显改变 ,但SERCA已显著减少。结论　Ca2 -ATP酶活性和蛋白水平的降低是低氧钙转运异常的主要原因     

Both Hypoxic Endothelial Cell Conditioned Medium and Hypoxia Elevate Intracellular Free Calcium in Pulmonary Artery Smooth Mu

ＢｏｔｈＨｙｐｏｘｉｃＥｎｄｏｔｈｅｌｉａｌＣｅｌｌＣｏｎｄｉｔｉｏｎｅｄＭｅｄｉｕｍａｎｄＨｙｐｏｘｉａＥｌｅｖａｔｅＩｎｔｒａｃｅｌｌｕｌａｒＦｒｅｅＣａｌｃｉｕｍｉｎＰｕｌｍｏｎａｒｙＡｒｔｅｒｙＳｍｏｏｔｈＭｕｓｃｌｅＣｅｌｌｓＨＵＱｉｎｇ－...     

Pathogenesis and the role of Ca2+ overload during myocardial ischemia/reperfusion

To study the regulation of [Na+]i and [Ca2+]i during myocardial ischemia/reperfusion, [Na+]i and [Ca2+]i were measured simultaneously using guinea pig ventricular myocytes which were dual-loaded with SBFI/AM and fluo-3/AM. It was suggested that: (1) [Na+]i increased during metabolic inhibition (MI: 3.3 mM amytal and 5 microM CCCP) by both the activated Na+ influx via Na+/H+ exchange and the suppressed Na+ extrusion via the Na+/K+ pump; (2) Na+/Ca2+ exchange was inhibited during MI, causing the dissociation between [Na+]i and [Ca2+]i; (3) Na+/Ca2+ exchange could be reactivated by energy repletion, resulting in a significant increase in [Ca2+], Furthermore, a Ca2+ influx via the reverse-mode of Na+/Ca2+ exchange may play a key role in the mechanism of Ca2+ overload on reoxygenation; and (4) cell contracture during MI was related to rigor due to energy depletion, while cell contracture after energy repletion was likely to be related to Ca2+ overload.     

参附注射液保护阿霉素心肌毒性机理研究

目的:观察参附注射液保护阿霉素心脏毒性的作用机理.方法:急性分离单个心肌细胞,运用TILLVISION钙离子荧光成像及分析系统,观察不同组间单个心肌细胞内游离钙离子的浓度变化.结果:阿霉素可引起心肌细胞内钙离子水平显著升高(P＜0.01),参附注射液干预可显著降低异常心肌细胞内游离钙离子浓度;同时,参附注射液还可抑制咖啡因诱导的内钙释放.结论:参附注射液对阿霉素心脏毒性的保护作用可能是通过抑制肌浆网的内钙释放,避免心肌细胞内钙超载,从而维持细胞内钙离子水平,达到保护心肌的作用.