Lukyanenko V, Katina I E, Nasledov G A, Terentyev D A
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
Gen Physiol Biophys. 1995 Dec;14(6):515-23.
Effects of beta-agonists isoproterenol (Isp) and adrenaline (Adr) and beta-adrenoblocker obsidan (Obs) on the voltage-dependent calcium currents in cultured embryonic skeletal myocytes were studied at various stages of development ranging from day 2 to 10, using the whole-cell patch-clamp technique at 19-21 degrees C. Adr (or Isp) in concentrations 0.1-10 mumol/l increases the amplitude of both the slow dihydropyridine(DHP)-sensitive calcium current (ICa) and the fast-activated DHP-insensitive ICa. From day 2 to 6 after myoblast plating, Adr and Isp did not change the amplitude of ICa at all or slightly increased it. Obvious strong positive effects (an approximately twofold amplitude increase) on the calcium channels have been observed in 7-10-day-old myocytes only. beta-adrenoblocker obsidan known to abolish the positive beta-agonist effect, had a positive effect on membrane calcium currents. It may have been a result of the immaturity of the beta-adrenergic regulatory system of the myocytes. It is concluded that the beta-adrenergic regulatory complex can stimulate the activity of the fast and the slow voltage-dependent calcium channels of the frog skeletal myocytes, and that there is a distinct developmental stage at which a functioning beta-adrenergic regulatory complex appears in the membrane of skeletal myocytes.
在19 - 21摄氏度下，使用全细胞膜片钳技术，研究了β - 激动剂异丙肾上腺素（Isp）和肾上腺素（Adr）以及β - 肾上腺素能阻滞剂奥西丹（Obs）对培养的胚胎骨骼肌细胞中电压依赖性钙电流在发育第2天至第10天各个阶段的影响。浓度为0.1 - 10 μmol / l的Adr（或Isp）可增加缓慢的二氢吡啶（DHP）敏感钙电流（ICa）和快速激活的DHP不敏感ICa的幅度。在成肌细胞接种后的第2天至第6天，Adr和Isp对ICa的幅度完全没有改变或略有增加。仅在7 - 10日龄的肌细胞中观察到对钙通道有明显的强烈正向作用（幅度增加约两倍）。已知能消除β - 激动剂正向作用的β - 肾上腺素能阻滞剂奥西丹对膜钙电流有正向作用。这可能是由于肌细胞的β - 肾上腺素能调节系统不成熟所致。结论是，β - 肾上腺素能调节复合物可刺激青蛙骨骼肌细胞快速和缓慢的电压依赖性钙通道的活性，并且在骨骼肌细胞膜中出现功能正常的β - 肾上腺素能调节复合物存在一个明显的发育阶段。
