Spatial and temporal resolution of serotonin-induced changes in intracellular calcium in a cultured arterial smooth muscle cell line.
Spatial and temporal resolution of serotonin-induced changes in intracellular calcium in a cultured arterial smooth muscle cell line.
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培养的动脉平滑肌细胞系中血清素诱导的细胞内钙变化的空间和时间分辨率。
DOI：
10.1159/000158870
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Goldman,WF
中科院分区：
文献类型：
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作者：
Goldman,WF
利用fura-2和数字成像显微镜研究了血清素（5-HT）在培养的a7r5细胞中引起的Ca2+瞬态（1-2µM）。Fura-2通过与其乙酰氧基甲酯类似物Fura-2 /AM的孵育或通过atp诱导的肌膜的瞬时渗透使游离的Fura-2直接进入细胞而被引入细胞。通过前一种方法负载的未刺激细胞的细胞质Ca2+分布是不均匀的，部分反映了细胞质和肌浆网（SR）中Ca2+的分离池。相比之下，Ca2+在fura-2负载的细胞中通过瞬态渗透分布均匀；这反映了fura-2对细胞质的限制。这些细胞中的平均Ca2+明显低于加载fura-2/ am的细胞，因为SR Ca2+影响加载fura-2/ am的细胞的fura-2信号，但不影响加载游离fura-2的细胞。在5- ht诱导的Ca2+瞬态过程中，两种加载方法测量的Ca2+分布差异也很明显。在fura-2/ am负载的细胞中，5- ht诱发的Ca2+瞬态的上升期的空间和时间分辨率显示，Ca2+瞬态的发作首先表现为Ca2+升高的小区域，随后扩大，直到几乎所有细胞的非核区域都存在明显的细胞内Ca2+水平峰值。Ca2+在不同细胞区域的上升速率不同，细胞核反应最慢。
Ca2+transients (1–2 µM) evoked by serotonin (5-HT) in cultured A7r5cells were studied using fura-2 and digital imaging microscopy. Fura-2 was introduced into cells either by incubation with its acetoxymethyl ester analogue fura-2/AM or by transient ATP-induced permeabilization of the sarcolemma such that the free fura-2 entered the cell directly. The distribution of cytoplasmic Ca2+in unstimulated cells loaded by the former method was heterogeneous, reflecting, in part, separate pools of Ca2+in the cytosol and sarcoplasmic reticulum (SR). In contrast, the distribution of Ca2+was uniform in cells loaded with fura-2 by transient permeabilization; this reflected the restriction of fura-2 to the cytosol. Average Ca2+in these cells was substantially lower than that in fura-2/AM-loaded cells, because SR Ca2+influences the fura-2 signal from fura-2/AM-loaded cells, but not from cells loaded with free fura-2. The differences in the Ca2+distribution measured by the two loading methods were also evident during the course of 5-HT-evoked Ca2+transients. Spatial and temporal resolution of the rising phase of 5-HT-evoked Ca2+transients in fura-2/AM-loaded cells revealed that the onset of the Ca2+transients was first manifested as small regions of elevated Ca2+that subsequently expanded until peak apparent intracellular Ca2+levels were present in virtually all of the nonnuclear regions of the cells. The rate of rise of Ca2+varied in different cell regions with the nucleus responding the slowest.