Effect of beta-adrenoceptor activation on [Ca2+]i regulation in murine skeletal myotubes.
Effect of beta-adrenoceptor activation on [Ca2+]i regulation in murine skeletal myotubes.
复制标题
β-肾上腺素受体激活对小鼠骨骼肌管 [Ca2]i 调节的影响。
DOI：
10.1152/ajpcell.1999.276.5.c1038
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Sieck,GC
中科院分区：
文献类型：
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作者：
Prakash,YS;vanderHeijden,HF;Gallant,EM;Sieck,GC
本研究使用实时共聚焦显微镜检查β2肾上腺素受体激动剂沙丁胺醇对新生小鼠肢体肌肉肌管细胞内Ca 2+浓度（[Ca 2 +]i）调节的影响。兰尼碱受体和骨骼肌肌球蛋白的免疫细胞化学染色证实了肌节的存在。肌管显示自发的和ACh诱导的快速（<2 ms上升时间）[Ca ~（2+）] i。低浓度和高浓度的沙丁胺醇对[Ca ~（2+）] i ~（2+）的传递都有频率调制作用。暴露于α-银环蛇毒素和河豚毒素可抑制ACh诱导的[Ca ~（2+）] i的变化和对低浓度沙丁胺醇的反应，但对高浓度的反应无影响。预暴露于咖啡因抑制随后的[Ca 2 +] i响应较低浓度的沙丁胺醇和显着钝化的响应较高的浓度。预先暴露于沙丁胺醇可降低咖啡因引起的[Ca ~（2+）] i反应。硝苯地平或PN-200-110抑制二氢吡啶敏感性Ca 2+通道并不能阻止高浓度沙丁胺醇诱导的[Ca 2 +] i升高。沙丁胺醇的作用由膜渗透类似物二丁酰腺苷3′，5 ′-环一磷酸模拟。这些数据表明，沙丁胺醇在骨骼肌中的作用主要涉及增强肌浆网Ca 2+释放。
The present study used real-time confocal microscopy to examine the effects of the β2-adrenoceptor agonist salbutamol on regulation of intracellular Ca2+concentration ([Ca2+]i) in myotubes derived from neonatal mouse limb muscles. Immunocytochemical staining for ryanodine receptors and skeletal muscle myosin confirmed the presence of sarcomeres. The myotubes displayed both spontaneous and ACh-induced rapid (<2-ms rise time) [Ca2+]itransients. The [Ca2+]itransients were frequency modulated by both low and high concentrations of salbutamol. Exposure to α-bungarotoxin and tetrodotoxin inhibited ACh-induced [Ca2+]itransients and the response to low concentrations of salbutamol but not the response to higher concentrations. Preexposure to caffeine inhibited the subsequent [Ca2+]iresponse to lower concentrations of salbutamol and significantly blunted the response to higher concentrations. Preexposure to salbutamol diminished the [Ca2+]iresponse to caffeine. Inhibition of dihydropyridine-sensitive Ca2+channels with nifedipine or PN-200-110 did not prevent [Ca2+]ielevations induced by higher concentrations of salbutamol. The effects of salbutamol were mimicked by the membrane-permeant analog dibutyryl adenosine 3′,5′-cyclic monophosphate. These data indicate that salbutamol effects in skeletal muscle predominantly involve enhanced sarcoplasmic reticulum Ca2+release.