Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and ...Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca2+]i elevation was abolished in the presence of the ETA receptor blocker BQ123, but was not affected by the ETB receptor blocker BQ788. ET-1-induced an increase in [Ca2+]i, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.展开更多
The mechanism of peroxynitrite (ONOO -)induced [Ca 2+ ] i increase in single MN9D cell (Dopaminergic neuroblastoma cell line) was studied by using Fura2 microfluorometric technique. The results show that ONOO - caused...The mechanism of peroxynitrite (ONOO -)induced [Ca 2+ ] i increase in single MN9D cell (Dopaminergic neuroblastoma cell line) was studied by using Fura2 microfluorometric technique. The results show that ONOO - caused a rapid increase of [Ca 2+ ] i when ONOO - was puffed to the cell. Removing Ca 2+ from the bath or using calcium channel antagonist (CdCl 2, Nifedipine) greatly inhibited the [Ca 2+ ] i increase induced by ONOO -, suggesting that the opening of LCa 2+ channel makes a great contribution to the [Ca 2+ ]\-i increase. The effect of sulfhydryl reductive agent (DTT) on ONOO -induced [Ca 2+ ]\-i increase suggests that ONOO -activating LCa 2+ channel is partly related to its oxidative speciality.展开更多
目的:研究850 nm波长微激光对肥大细胞照射后胞内钙离子浓度的影响。方法:实验前12 h,将肥大细胞接种于激光共聚焦专用培养皿中,然后用D-Hank’s液洗涤3次,加入2 m L D-Hank’s液,按照照射时间不同共分六组(Control,1 min,2 min,2.5 min...目的:研究850 nm波长微激光对肥大细胞照射后胞内钙离子浓度的影响。方法:实验前12 h,将肥大细胞接种于激光共聚焦专用培养皿中,然后用D-Hank’s液洗涤3次,加入2 m L D-Hank’s液,按照照射时间不同共分六组(Control,1 min,2 min,2.5 min,3 min,4 min),其中,空白对照组不进行激光照射处理;激光照射后,弃去D-Hank’s液,加入含有Fluo-3/AM的D-Hank’s液1 m L,放入培养箱中孵育30 min后,用D-Hank’s液洗涤3次去除胞外多余的Fluo-3/AM,再加入含有10%FBS的D-Hank’s液2 m L,置激光扫描共聚焦显微镜检测。结果:空白对照组中细胞内未见荧光,说明此时胞内无钙离子,但从1 min开始在细胞中发现荧光,而且发现随着照射时间的加长,其荧光强度越来越强,这可能与微激光照射时间越长从而刺激胞内出现更多的钙离子有关。从上面的实验说明850 nm微激光能作为仿灸仪器的光源。展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 200830870910).
文摘Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca2+]i elevation was abolished in the presence of the ETA receptor blocker BQ123, but was not affected by the ETB receptor blocker BQ788. ET-1-induced an increase in [Ca2+]i, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.
文摘The mechanism of peroxynitrite (ONOO -)induced [Ca 2+ ] i increase in single MN9D cell (Dopaminergic neuroblastoma cell line) was studied by using Fura2 microfluorometric technique. The results show that ONOO - caused a rapid increase of [Ca 2+ ] i when ONOO - was puffed to the cell. Removing Ca 2+ from the bath or using calcium channel antagonist (CdCl 2, Nifedipine) greatly inhibited the [Ca 2+ ] i increase induced by ONOO -, suggesting that the opening of LCa 2+ channel makes a great contribution to the [Ca 2+ ]\-i increase. The effect of sulfhydryl reductive agent (DTT) on ONOO -induced [Ca 2+ ]\-i increase suggests that ONOO -activating LCa 2+ channel is partly related to its oxidative speciality.
文摘目的:研究850 nm波长微激光对肥大细胞照射后胞内钙离子浓度的影响。方法:实验前12 h,将肥大细胞接种于激光共聚焦专用培养皿中,然后用D-Hank’s液洗涤3次,加入2 m L D-Hank’s液,按照照射时间不同共分六组(Control,1 min,2 min,2.5 min,3 min,4 min),其中,空白对照组不进行激光照射处理;激光照射后,弃去D-Hank’s液,加入含有Fluo-3/AM的D-Hank’s液1 m L,放入培养箱中孵育30 min后,用D-Hank’s液洗涤3次去除胞外多余的Fluo-3/AM,再加入含有10%FBS的D-Hank’s液2 m L,置激光扫描共聚焦显微镜检测。结果:空白对照组中细胞内未见荧光,说明此时胞内无钙离子,但从1 min开始在细胞中发现荧光,而且发现随着照射时间的加长,其荧光强度越来越强,这可能与微激光照射时间越长从而刺激胞内出现更多的钙离子有关。从上面的实验说明850 nm微激光能作为仿灸仪器的光源。
