The nitrendipine-sensitive Ca2+ channel in chick muscle cells and its appearance during myogenesis in vitro and in vivo.
The nitrendipine-sensitive Ca2+ channel in chick muscle cells and its appearance during myogenesis in vitro and in vivo.
复制标题
鸡肌细胞中尼群地平敏感的 Ca2 通道及其在体外和体内成肌过程中的出现。
DOI：
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发表时间：
1984
影响因子：
4.8
通讯作者：
M. Lazdunski
中科院分区：
文献类型：
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作者：
A. Schmid;J. Renaud;M. Fosset;J. Méaux;M. Lazdunski
本文用~(45)Ca~(2+)通量技术和[~3H]尼群地平结合实验研究了培养的鸡骨骼肌管对尼群地平敏感的钙通道。当培养的鸡肌管极化时，尼群地平对钙摄取不敏感。而去极化揭示了45Ca~(2+)内流的新成分，该成分可被尼群地平抑制。尼群地平浓度为0.7 nM时，出现半峰抑制。该值与尼群地平结合实验中测得的离解常数Kd=0.4 nM相似。在体外成肌细胞中，尼群地平受体缺失，并且与融合过程平行出现。在体内观察到了两个阶段的结合增加。第一种发生在胚胎时期，具有与体外发育相同的特性。第二阶段发生在孵化附近，与尼群地平受体数量的大幅增加相对应。这种增加伴随着尼群地平对其受体亲和力的降低4到10倍。慢性去神经支配使尼群地平受体的数目进一步增加，在去神经支配15天时达到约2倍。文中还讨论了这些通道在横管中的特殊定位和神经支配的结果。
The nitrendipine-sensitive Ca2+ channel of chick skeletal myotubes in culture has been studied using both the 45Ca2+ flux technique and [3H]nitrendipine binding experiments. Ca2+ uptake is insensitive to nitrendipine when chick myotubes in culture are polarized. Whereas depolarization reveals a new component of 45Ca2+ influx which is inhibited by nitrendipine. Half-maximal inhibition occurs at a nitrendipine concentration of 0.7 nM. This value is similar to the dissociation constant Kd = 0.4 nM found in [3H]nitrendipine binding experiments. During myogenesis in vitro the nitrendipine receptor is absent in myoblasts and appears in parallel with the fusion process. Two stages of increased binding have been observed in vivo. The first one, which occurs during embryonic life, has the same properties as in the in vitro development. The second stage occurs near hatching and corresponds to a large increase in the number of nitrendipine receptors. This increase is accompanied by a decrease of affinity of nitrendipine for its receptor by a factor of 4 to 10. Chronic denervation produces a further increase in the number of nitrendipine receptors which reaches a factor of about 2 at 15 days of denervation. Results are discussed in relation to the particular localization of these channels in transverse tubules and with the innervation.