Identification and spatiotemporal characterization of spontaneous Ca2+ sparks and global Ca2+ oscillations in retinal arteriolar smooth muscle cells.
Identification and spatiotemporal characterization of spontaneous Ca2+ sparks and global Ca2+ oscillations in retinal arteriolar smooth muscle cells.
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DOI：
10.1167/iovs.04-0719
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发表时间：
2004-12
影响因子：
4.4
通讯作者：
McGeown JG
中科院分区：
文献类型：
--
作者：
Curtis TM;Tumelty J;Dawicki J;Scholfield CN;McGeown JG
目的：研究完整视网膜小动脉内微血管平滑肌细胞（MVSM）的自发性钙火花和整体性钙振荡，并探讨其时空特性和生理功能。视网膜小动脉从新鲜分离的大鼠视网膜机械分散，并加载与Ca 2+敏感染料Fluo-4。[Ca 2 +]i的变化在MVSM细胞原位成像，使用共聚焦扫描激光显微镜在XY或线扫描模式。XY扫描显示两个离散的本地化，自发的Ca 2+事件类似的Ca 2+火花，和更全球性和长期的Ca 2+瞬变，有时导致细胞收缩。在行扫描中，Ca 2+火花与先前在其他类型平滑肌中描述的相似，振幅（ΔF/F0）为0.81±0.04（平均值±SE），半峰全时长（FDHM）为23.62±1.15 ms，半峰全宽（FWHM）为1.25±0.05μm，频率为0.56±0.06 s−1。大约35%的火花具有延长的尾部（> 80 ms），类似于骨骼肌中描述的Ca 2+“余烬”。火花往往summated产生全球和长期的Ca 2+海拔上的Ca 2+火花叠加。这些火花出现的频率更高（2.86±025 s−1），并且在整个细胞中传播得更远（FWHM=1.67±0.08μm），但较小（ΔF/F0 = 0.69±0.04）。视网膜小动脉产生Ca 2+火花，其特征在自发Ca 2+信号周期的不同阶段有所不同。火花summate产生持续的Ca 2+瞬变与收缩，因此可能发挥重要的兴奋作用，在启动血管收缩。这值得进一步研究，尤其是因为Ca 2+火花似乎抑制了许多其他平滑肌细胞的收缩。
To identify spontaneous Ca2+ sparks and global Ca2+ oscillations in microvascular smooth muscle cells (MVSM) within intact retinal arterioles and to characterize their spatiotemporal properties and physiological functions. Retinal arterioles were mechanically dispersed from freshly isolated rat retinae and loaded with the Ca2+-sensitive dye Fluo-4. Changes in [Ca2+]i were imaged in MVSM cells in situ using confocal scanning laser microscopy in XY or line scan mode. XY scans revealed both discretely localised, spontaneous Ca2+ events resembling Ca2+ sparks, and more global and prolonged Ca2+ transients which sometimes led to cell contraction. In line-scans, Ca2+ sparks were similar to those previously described in other types of smooth muscle with an amplitude (ΔF/F0) of 0.81±0.04 (mean±SE), Full Duration Half Maximum (FDHM) of 23.62±1.15 ms, Full Width Half Maximum (FWHM) of 1.25±0.05μm and frequency of 0.56±0.06 s−1. Approximately 35% of sparks had a prolonged tail (>80ms), similar to Ca2+ ‘embers’ described in skeletal muscle. Sparks often summated to generate global and prolonged Ca2+ elevations on which Ca2+ sparks were superimposed. These sparks occurred more frequently (2.86±025 s−1) and spread further across the cell (FWHM=1.67±0.08μm), but were smaller (ΔF/F0 = 0.69±0.04). Retinal arterioles generate Ca2+ sparks whose characteristics vary during different phases of the spontaneous Ca2+-signalling cycle. Sparks summate to produce sustained Ca2+-transients associated with contraction and thus may play an important excitatory role in initiating vessel constriction. This deserves further study, not least because Ca2+ sparks appear to inhibit contraction in many other smooth muscle cells.
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DOI：
10.1085/jgp.20028514
发表时间：
2002-06
期刊：
The Journal of general physiology
影响因子：
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作者：
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2001-05-01
影响因子：
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影响因子：
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