Ca2+ channel agonist BAY‐k 8644 does not elicit Ca2+ release from skeletal muscle sarcoplasmic reticulum

FEBS Letters

Zorzato, Francesco¹  Margreth, Alfredo¹  Volpe, Pompeo¹  Salviati, Giovanni¹ 

[1] Centro di Studio per la Biologia e la Fisiopatologia Musculare del CNR, Istituto di Patologia Generale dell ‘Universita’ di Padova, via Loredan 16, 35131 Padova, Italy

关键词: BAY-k 8644;    Sarcoplasmic reticulum;    Ca2+ release;    Ca2+ pump;   

DOI  :  10.1016/0014-5793(85)80719-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

BAY-k 8644, a nifedipine analogue, promotes Ca²⁺ influx into excitable cells via plasma membrane voltage-sensitive Ca²⁺ channels. We report here that sarcoplasmic reticulum (SR) Ca²⁺ release channels are insensitive to BAY-k 8644, as studied in highly purified isolated fractions and in chemically skinned fibers of rabbit skeletal muscle. This result suggests that a subcellular heterogeneity exists among Ca²⁺ channels, at least with respect to drug-receptor sites. In the course of this study, however we found that BAY-k 8644 reversibly inhibits the SR Ca²⁺ pump, i.e., it decreases Ca²⁺ influx into the SR lumen, although at concentrations (IC₅₀ = 3-5 × 10⁻⁵M) much higher than those effective on voltage-sensitive Ca²⁺ channels.

【 授权许可】

Unknown