GAP JUNCTION-MEDIATED INTERCELLULAR DIFFUSION OF CA-2+ IN CULTURED HUMAN CORPORAL SMOOTH-MUSCLE CELLS
GAP JUNCTION-MEDIATED INTERCELLULAR DIFFUSION OF CA-2+ IN CULTURED HUMAN CORPORAL SMOOTH-MUSCLE CELLS
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DOI：
10.1152/ajpcell.1992.263.2.c373
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发表时间：
1992-08-01
影响因子：
--
通讯作者：
SPRAY, DC
中科院分区：
文献类型：
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作者：
CHRIST, GJ;MORENO, AP;SPRAY, DC
采用钙敏感探针fura-2的比值成像技术研究了海绵体血管平滑肌细胞培养物中细胞内钙浓度和细胞间钙通过间隙连接的通量。显微注射技术表明，游离fura-2酸可通过培养细胞间的间隙连接自由扩散。fura-2负载细胞的静息细胞内钙水平为176.9 +/- 10.5。在对苯肾上腺素和钙离子载体A23187的反应中，细胞内钙的显著增加。Ca2+微注射到单个平滑肌细胞中总是导致相邻细胞内钙水平的显著增加，尽管时间延迟；这种细胞间钙通量通过抑制2mm庚醇的间隙连接通讯而被可逆地阻断。然而，尽管将d -肌醇1,4,5-三磷酸[Ins(1,4,5)P3]微注射到单个平滑肌细胞中总是会显著增加注射细胞内的钙水平，但与Ca2+注射相比，Ins(1,4,5)P3对细胞间Ca2+扩散的影响更大。这些研究表明，Ca2+，也许还有Ins(1,4,5)P3，可以通过间隙连接通道在平滑肌细胞之间扩散。
Ratio imaging using the calcium-sensitive probe fura-2 was employed to study intracellular calcium concentrations and intercellular calcium flux through gap junctions in homogeneous vascular smooth muscle cell cultures derived from the human corpora cavernosa. Microinjection techniques demonstrated that fura-2 free acid was freely diffusible through gap junctions between cultured cells. The resting intracellular calcium level in fura-2-loaded cells was 176.9 +/- 10.5. A robust increase in intracellular calcium was seen in response to both phenylephrine and the calcium ionophore A23187. Microinjection of Ca2+ into individual smooth muscle cells always resulted in significant, although temporally delayed, increases in intracellular calcium levels in adjacent cells; this intercellular calcium flux was reversibly blocked by inhibition of gap junctional communication with 2 mM heptanol. However, although microinjection Of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] into individual smooth muscle cells always produced significant increases in intracellular calcium levels in the injected cell, the intercellular spread of Ca2+ in response to Ins(1,4,5)P3 Was more variable than for Ca2+ injections. These studies demonstrate that Ca2+ , and perhaps Ins(1,4,5)P3 as well, can diffuse between smooth muscle cells through gap junction channels.