Ryanodine modulation of 45Ca efflux and tension in rabbit aortic smooth muscle.
Ryanodine modulation of 45Ca efflux and tension in rabbit aortic smooth muscle.
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Ryanodine 对兔主动脉平滑肌 45Ca 流出和张力的调节。
DOI：
10.1007/bf00581127
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
vanBreemen,C
中科院分区：
文献类型：
--
作者：
Hwang,KS;vanBreemen,C
测定了兰诺定对兔离体主动脉等长张力发育、细胞净钙含量和45Ca外流的影响。组织用10μM ryanodine预处理30分钟，可降低去甲肾上腺素(NE)引起的无细胞外钙条件下的主动脉环张力，同时可减少NE刺激的45Ca外流。单独兰诺定引起45Ca外流延迟适度增加，缓慢增加损失分数，从0.02/分钟增加到0.03/分钟，而不增加任何张力。随着~(45)Ca外流增加，细胞内净钙含量降低。在45Ca外流过程中依次给予兰诺定和去甲肾上腺素，我们发现兰诺定引起的45Ca丢失与抑制NE诱导的45Ca释放之间存在定量的相关性。我们认为，10μM ryanodine抑制去甲肾上腺素引起的收缩是细胞内钙耗竭的结果，而不是抑制钙释放的结果。
The effects of ryanodine on isometric tension development, net cellular Ca content and45Ca efflux were measured in the isolated rabbit aorta. Pretreatment of the tissue with 10 μM ryanodine for 30 min reduced the norepinephrine (NE)-induced tension of the aortic rings bathed in the absence of extracellular Ca2+in parallel with a reduction in the NE-stimulated45Ca efflux. Ryanodine alone caused a delayed moderate increase in45Ca efflux, slowly increasing the fractional loss from 0.02/min to 0.03/min, without any increase in tension. The increased45Ca efflux was accompanied by a decrease in the net cellular Ca content. When ryanodine and NE were administered in sequence during45Ca efflux, we found a quantitative correlation between the ryanodine induced loss of45Ca and the inhibition of the NE-induced45Ca release. We conclude that the inhibition of the NE-induced contraction by 10 μM ryanodine is the result of depletion of Ca from intracellular stores rather than inhibitions of Ca2+release.