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...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.展开更多
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, mo...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.展开更多
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 cerebr...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.展开更多
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 quiesc...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.展开更多
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 indica...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.展开更多
MOST mammalian oocytes are arrested at the metaphase of second meiotic division (MⅡ) after maturation. The intracellular calcium ([Ca<sup>2+</sup>]<sub>i</sub>) in MⅡ eggs rises repetitivel...MOST mammalian oocytes are arrested at the metaphase of second meiotic division (MⅡ) after maturation. The intracellular calcium ([Ca<sup>2+</sup>]<sub>i</sub>) in MⅡ eggs rises repetitively from basal level of 40—100 nmol/L to peak level of 1000 nmol/L, which is termed Ca<sup>2+</sup> oscillation. It is established that [Ca<sup>2+</sup>]<sub>1</sub> increase is the primary signal responsible for the resumption of second meiotic division. Previous investigations largely focused on the fertilization-induced [Ca<sup>2+</sup>]<sub>i</sub>展开更多
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 sig...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.展开更多
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. W...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.展开更多
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 phenome...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.展开更多
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China,No.81171239Frontier Research Project of Central South University in China,No.2177-721500065the Graduate Degree Thesis Innovation Foundation of Central South University in China
文摘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.
文摘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.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10575041 and 10747005.
文摘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.
文摘MOST mammalian oocytes are arrested at the metaphase of second meiotic division (MⅡ) after maturation. The intracellular calcium ([Ca<sup>2+</sup>]<sub>i</sub>) in MⅡ eggs rises repetitively from basal level of 40—100 nmol/L to peak level of 1000 nmol/L, which is termed Ca<sup>2+</sup> oscillation. It is established that [Ca<sup>2+</sup>]<sub>1</sub> increase is the primary signal responsible for the resumption of second meiotic division. Previous investigations largely focused on the fertilization-induced [Ca<sup>2+</sup>]<sub>i</sub>
文摘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.
文摘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.
文摘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.