Effects of Aconitine on [Ca^(2+)] 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.

The fertilization-induced Ca^(2+) oscillation in mouse oocytes is cytoplasmic maturation dependent

Mature eggs (at metaphase Ⅱ stage) produce a series of Ca2+ oscillation at fertilization. To define whether the fertilization-induced Ca2+ oscillation is restrict to the metaphase Ⅱ eggs and cell cycle dependent, mouse oocytes at prophase Ⅰ (arrested at germinal vesicle stage),metaphase Ⅰ, metaphase Ⅱ, as well as the pronuclear embryos at interphase of the first mitotic division derived from fertilization or parthenogenetic activation were inseminated after removal of zona pellucida. The results show that the fertilization-induced Ca2+ oscillation is not specific to metaphase Ⅱ eggs. This is supported by the fact that immature oocytes generated the Ca2+ oscillations at fertilization regardless of their nuclear progression from prophase Ⅰ to metaphase Ⅰ (in vitro matured) stage. More interestingly, it was first found that pronuclear embryos at interphase derived from parthenogenetic activation showed Ca2+ oscillations in response to fertilization while the zygotes at interphase did not after reinsemination or intracytoplasmic injection of sperm extracts which induce Ca2+ oscillations in MII eggs. This suggests that the ability of oocytes to generate Ca2+ oscillation in response to sperm penetration is not regulated in a cell cycle dependent manner but dependent on the cytoplasmic maturation.

Ca^(2+)、pH在花粉及萌发花粉管生长中的作用研究进展

花粉正常萌发并生长是精细胞顺利到达胚囊并实现受精作用的前提,因而是高等植物有性生殖的一个关键环节.花粉管生长涉及一系列过程,而花粉 或花粉管 内外的Ca2+和pH的变化与花粉萌发、花粉管生长有着密切的关系.比较详细地论述了Ca2+和pH在花粉萌发、花粉管生长过程中的分布特点、生理功能及分子机制.

动态IP_3-Ca^(2+)振荡模型的数值分析

通过改进J.W.Shuai和P.Jung钙振荡模型,得到与IP3浓度相关的动态IP3-Ca2+振荡模型。利用改进模型,数值分析依赖性参数#和钙通道数目N对Ca2+振荡的影响,得到Ca2+振荡关于参数#的分叉图、Ca2+振荡与IP3振荡的一致性、钙通道数目N对Ca2+振荡的影响等。这些模型结果显示了Ca2+振荡的特性。

肝细胞内Ca^(2+)振荡对磷酸化-去磷酸化循环过程的动力学研究

目的 从理论上阐述了Ca2 + 振荡对肝细胞中糖原降解的磷酸化 去磷酸化循环过程的调控效应。方法 应用Ca2 + 振荡模型观察Ca2 + 振荡对肝细胞中糖原降解的磷酸化循环过程的调控。结果 Ca2 + 振荡可以增强细胞对激素反应的潜力。肝细胞中的磷酸化 去磷酸化动力学过程 ,在Ca2 + 振荡的调控下 ,其糖原磷酸化酶的浓度呈现同频、同步振荡。结论 Ca2 + 振荡将会提高细胞中信息的传递效率和特异性。

玻璃化冷冻对哺乳动物卵母细胞Ca^2+的影响机制

卵母细胞冷冻保存是胚胎生物技术(如体外受精、胞浆内单精子注射、体细胞克隆)的重要组成部分,对优良种畜和濒危动物种质资源保存,加速家畜品种改良进程都具有重要意义。与常规冷冻法相比,玻璃化冷冻具有操作简单、降温速率快、耗时短、冷冻效率高等优点,被越来越广泛地应用于家畜卵母细胞的冷冻保存。然而,与新鲜卵母细胞相比,玻璃化冷冻卵母细胞的受精率及发育能力仍不理想,这严重影响了玻璃化冷冻卵母细胞的应用潜力。玻璃化冷冻会引起卵母细胞Ca^(2+)浓度升高及钙振荡模式异常,导致其透明带硬化、受精信号紊乱等问题。综合前人研究进展,作者分析了玻璃化冷冻对胞内Ca^(2+)浓度、钙振荡模式的影响和作用机制,并指出胞外Ca^(2+)内流和胞内钙库Ca^(2+)释放是导致冷冻卵母细胞胞内Ca^(2+)浓度升高的主要原因,1,4,5-三磷酸肌醇(IP3)Ⅰ型受体分布异常和线粒体损伤可能是导致冷冻卵母细胞钙振荡模式异常的重要原因,以期为正向调控冷冻卵母细胞Ca^(2+)浓度及钙振荡模式提供技术参考,从而进一步提高玻璃化冷冻卵母细胞的受精和后续的发育能力。

高血糖对小鼠卵母细胞Ca^(2+)振荡和卵泡颗粒细胞肿瘤坏死因子相关凋亡诱导配体表达的影响

目的探讨高血糖对小鼠卵母细胞Ca2+振荡和卵泡颗粒细胞肿瘤坏死因子相关凋亡诱导配体(TRAIL)表达的影响。方法出生后20d ICR雌鼠,用链脲酶素建立急性高血糖模型;高血糖模型雌鼠及正常雌鼠注射10IU/只孕马血清促性腺激素(PMSG)和人绒毛膜促性腺激素(hCG)超排卵,注射hCG后0h、2h、6h和10h取生发泡(GV)期卵母细胞,双光子激光扫描共焦显微镜检测GV期卵母细胞的Ca2+振荡;hCG注射后6h、10h取卵丘-卵母细胞复合体(COC),利用免疫荧光、Western blotting检测TRAIL的表达。结果 1.高血糖组卵母细胞Ca2+振荡频率高于正常对照组,于hCG注射后2h、6h差异显著(P<0.05);2.免疫荧光、Western blotting蛋白半定量检测显示,高血糖组颗粒细胞TRAIL表达量高于正常对照组,于hCG注射后6h、10h差异有显著性(P<0.05)。结论高血糖加快小鼠未成熟卵母细胞Ca2+振荡的频率;高血糖促进小鼠卵泡颗粒细胞TRAIL的表达。

IP_3-Ca^(2+)振荡模型的复杂动态

主要运用中心流形定理和分岔理论讨论了IP3-Ca2+振荡模型的非线性动态,从理论上严格证明了系统不仅存在Saddle-node分岔和Hopf分岔,而且揭示了系统振荡现象的产生和消失分别是由于平衡点发生Supercritical Hopf分岔和Subcritical Hopf分岔所导致的。通过运用matlab软件进行数值模拟,验证了理论分析结果的正确性。

Changes in secretory pathway Ca^(2+)-ATPase 2 following focal cerebral ischemia/reperfusion injury

This study aimed to investigate changes in secretory pathway Ca2＋-ATPase 2 expression following cerebral ischemia/reperfusion injury, and to define the role of Ca2＋-ATPases in oxidative stress. A rat model of cerebral ischemia/reperfusion injury was established using the unilateral middle cerebral artery occlusion method. Immunohistochemistry and reverse transcription-PCR assay results showed that compared with the control group, the expression of secretory pathway Ca2＋-ATPase 2 protein and mRNA in the cerebral cortex and hippocampus of male rats did not significantly change during the ischemic period. However, secretory pathway Ca2＋-ATPase 2 protein and mRNA expression reduced gradually at 1, 3, and 24 hours during the reperfusion period. Our experimental findings indicate that levels of secretory pathway Ca2＋-ATPase 2 protein and mRNA expression in brain tissue change in response to cerebral ischemia/reperfusion injury.

Update on vascular endothelial Ca^(2+) signalling:A tale of ion channels,pumps and transporters

A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which arelocated both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.

大黄素对体外培养Cajal间质细胞钙离子振荡功能的影响

目的:探讨大黄素对体外培养Cajal间质细胞钙离子振荡的影响,从而进一步揭示大黄素等促进胃肠动力的分子机制方法:体外培养小鼠ICC,体外添加大黄素,应用钙离子指示剂标记细胞内钙离子含量,在激光共聚焦显微镜下动态观察其钙离子振荡功能的变化。结果:免疫荧光鉴定结果证实体外培养细胞为ICC,体外培养ICC具有钙离子振荡功能,大黄素能显著增强其钙离子振荡的频率和振幅。结论:大黄素能显著增强体外培养ICC钙离子振荡功能,可能是其促进胃肠动力的重要机制。

以Mn^(2+)催化的α—酮戊二酸振荡反应的研究

本文利用实验中得到的电动势随时间变化的E～t图,研究了α—酮戊二酸(以α—Ke表示)—KBrO_3—H_2SO_4—丙酮(以Act表示)体系的Mn^(2+)催化下的振荡反应及许多因素对振荡反应的影响,根据实验结果及振荡反应的一般机理,探讨了该体系的振荡机理,归纳出振荡反应参数与反应物浓度之间存在的关系式,并对实验现象作了定性的说明。

Coupling Effect of Ion Channel Clusters on Calcium Signalling

Based on a modified intracellular Ca^2＋ model involving diffusive coupling of two calcium ion channel dusters, the effects of coupling on calcium signalling are numerically investigated. The simulation results indicate that the diffusive coupling of dusters together with internal noise determine the calcium dynamics of single duster, and for either homogeneous or heterogeneous coupled dusters, the synchronization of dusters, which is important to calcium signalling, is enhanced by the coupling effect.

Sperm-induced Ca^(2+) oscillations in mouse maturing oocytes and postovulatory ageing eggs

MOST mammalian oocytes are arrested at the metaphase of second meiotic division （MⅡ） after maturation. The intracellular calcium ([Ca2+]i) in MⅡ eggs rises repetitively from basal level of 40—100 nmol/L to peak level of 1000 nmol/L, which is termed Ca2+ oscillation. It is established that [Ca2+]1 increase is the primary signal responsible for the resumption of second meiotic division. Previous investigations largely focused on the fertilization-induced [Ca2+]i

Water Channels Are Involved in Stomatal Oscillations Encoded by Parameter-Specific Cytosolic Calcium Oscillations

Earlier studies have shown that various stimuli can induce specific cytosolic calcium （[Ca^2＋]cyt） oscillations in guard cells and various oscillations in stomatal apertures. Exactly how [Ca^2＋]cyt oscillation signaling functions in stomatal oscillation is not known. In the present study, the epidermis of broad bean （Vicia faba L.） was used and a rapid ion-exchange treatment with two shifting buffers differing in K^＋ and Ca^2＋ concentrations was applied. The treatment for fivetransients at a 10-min transient period induced clear and regular stomatal oscillation. However, for other transient numbers and periods, the treatments induced some Irregular oscillations or even no obvious oscillations in stomatal aperture. The results indicate that stomatal oscillation Is encoded by parameter-specific [Ca^2＋]cyt oscillation： the parameters of [Ca^2＋]cyt oscillation affected the occurrence rate and the parameters of stomatal oscillation. The water channel inhibitor HgCl2 completely Inhibited stomatal oscillation and the inhibitory effect could be partially reversed by β-mercaptoethanol （an agent capable of reversing water channel inhibition by HgCl2）. Other Inhibitory treatments against Ion transport （i.e. the application of LaCIs, EGTA, or tetraethylammonlum chloride （TEACI）） weakly impaired stomatal oscillation when the compounds were added after rapid ion-exchange treatment. If these compounds were added before rapid-ion exchange treatment, the inhibitory effect was much more apparent （except In the case of TEACI）. The results of the present study suggest that water channels are involved In stomatal oscillation as a downstream element of [Ca^2＋]cyt oscillation signaling.

扶正抑瘤颗粒对小鼠移植性肿瘤细胞间通讯的影响

目的:观察扶正抑瘤颗粒(红芪、当归、墓头回、莪术)含药血清对荷瘤小鼠H22细胞的凋亡和肿瘤细胞间通讯的影响。方法:Annexin V/PI双染法检测FYK含药血清对H22细胞凋亡情况的影响;应用共聚焦激光显微镜检测H22细胞RNA、DNA、[Ca2+]、细胞间通讯状况。结果:扶正抑瘤颗粒含药血清可引起H22细胞的凋亡,细胞RNA、DNA含量降低,[Ca2+]升高,细胞间通讯状况得到改善。结论:扶正抑瘤颗粒含药血清抑制H22细胞的增殖,并提高肿瘤细胞[Ca2+],阻止肿瘤细胞分裂。

植物细胞中钙信号的时空多样性与信号转导

近年来 ,对钙信号的研究 ,包括对钙信号的产生、传导及最终靶蛋白的研究 ,越来越受到人们的重视。植物生长发育许多过程的信息传递 ,包括对各种内外刺激的反应都涉及到钙信号。钙信号的产生及传导是通过胞质自由钙离子的浓度变化来实现的。本文综述了胞质自由钙离子的测定、钙信号的时空多样性及钙信号的靶蛋白如CaM、Ca2 +依赖的蛋白激酶、钙调磷酸酶、磷脂酰肌醇_磷脂酶C等方面的一些最新进展 ,展望了今后钙信号研究的方向及所用到的一些技术方法等。

细胞内钙离子体系中的双参数内信号随机共振

In a model of intercellular calcium ion system oscillations, internal stochastic resonance(ISR) is investigated under the modulation of two parameters, viz., degree of extracellular stimulation β and leak rate k f. When either β or k f is subjected to a noise, ISR can occur. When noise is added to the two parameters simultaneously, internal stochastic bi-resonance(ISBR) occurs. The distance to the bifurcation point is found to be able to enhance or suppress the ISBR, and to affect the number of peaks of ISR.

钙离子振荡体系中隐式和显式内信号随机共振

The dynamic behavior of calcium ion oscillations was investigated when noise was injected to the system located in a steady state and an oscillatory state,respectively.It was found that noise can contribute to phenomenon of implicit or explicit internal stochastic resonance(IISR or EISR),and that distance to bifurcation point was a key factor for controlling IISR or EISR.Then an external signal was added to the system,the result shows that IISR or EISR can not occur,implying an external signal destroys the cooperation of internal signal and noise.Furthermore,the difference and the similarity were discussed between IISR and EISR.

β-胡萝卜素拮抗促癌剂抑制细胞间隙连接通讯的机理探讨

运用荧光探针标记方法和放射免疫分析方法分别研究了细胞内游离Ｃａ２＋（［Ｃａ２＋］ｉ）和ｃＡＭＰ的变化与促癌剂ＴＰＡ抑制细胞间隙连接通讯（ＧａｐＪｕｎｃ－ｔｉｏｎａｌＩｎｔｅｒｃｅｌｕｌａｒＣｏｍｍｕｎｉｃａｔｉｏｎ，ＧＪＩＣ）功能的关系，以及β－胡萝卜素对这些变化的影响。结果表明：ＴＰＡ使［Ｃａ２＋］ｉ显著升高，ｃＡＭＰ水平显著降低，与对照组均有显著差异；β－胡萝卜素对［Ｃａ２＋］ｉ和ｃＡＭＰ的作用分别表现为降低和升高趋势，并对ＴＰＡ升高［Ｃａ２＋］ｉ、降低ｃＡＭＰ有一定的拮抗作用。提示：ＴＰＡ升高〔Ｃａ２＋〕ｉ、降低ｃＡＭＰ，影响间隙连接通道蛋白质磷酸化，这可能是其抑制细胞ＧＪＩＣ功能的重要原因之一，而β－胡萝卜素对［Ｃａ２＋］ｉ和ｃＡＭＰ的影响可能是其拮抗促癌剂抑制ＧＪＩＣ的部分作用机制。