Dihydropyridine‐sensitive Ca2+ channel in aneurally cultured human muscles Relationship between high‐affinity binding site and inhibition of calcium uptake

FEBS Letters

Engel, W.King¹  Askanas, Valerie¹  Desnuelle, Claude¹ 

[1] USC Neuromuscular Center, 637 South Lucas Avenue, Los Angeles, CA 90017, USA

关键词: Ca2+ channel;    Dihydropyridine receptor;    Muscle culture;   

DOI  :  10.1016/0014-5793(88)80649-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Dihydropyridine-sensitive Ca²⁺ channels and the relationship between binding of dihydropyridine derivatives and depolarization-induced Ca²⁺ uptake have been studied in aneurally cultured human muscle. Analysis of the equilibrium binding of the 1,4-dihydropyridine derivative (+)-PN200-110 revealed a single high-affinity binding site with a K _d of 0.15±0.05 nM and a B _max of 87±12 fmol/mg protein. Inhibition of (+)-[³H]PN200-110 binding by nitrendipine revealed a K _i of 0.8 nM for the nitrendipine-receptor complex. Depolarization of cultured human muscle achieved by elevating the K⁺ concentration increased the uptake ⁴⁵Ca²⁺ which was inhibited by nitrendipine with an IC₅₀ of 1.1 nM. This study demonstrates that aneurally cultured human muscle has dihydropyridine-sensitive voltage-dependent Ca²⁺ channels which are functional when the fibers are depolarized.

【 授权许可】

Unknown