Heterogeneity of Ca2+ gating of skeletal muscle and cardiac ryanodine receptors
Heterogeneity of Ca2+ gating of skeletal muscle and cardiac ryanodine receptors
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DOI：
10.1016/s0006-3495(97)78055-x
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发表时间：
1997-07-01
影响因子：
3.4
通讯作者：
Fleischer, S
中科院分区：
文献类型：
--
作者：
Copello, JA;Barg, S;Fleischer, S
本文研究了兔骨骼肌Ryanodine受体（骨骼肌RyR）和狗心肌RyR的单通道活性与细胞内[Ca ~（2+）]的关系。这些研究表明，对于骨骼和心脏RyR，存在通道的异质群体，而不是统一的行为。骨骼肌RyRs表现出两种极端的行为：1）低活性RyRs（LA骨骼RyR，类似于35%的通道）具有非常低的开放概率（P-o < 0.1），并且在Mg 2+（2 mM）和ATP（1 mM）存在下保持封闭;（2）高活性RyR（HA骨架RyR）在低[Ca ~（2+）]（0.6）条件下，在Mg ~（2+）和ATP存在和不存在时，其活性更高，P-o值表现出更大的异质性。心脏RyR对[Ca 2 +]抑制的敏感性（10倍）远低于骨骼RyR。心脏与骨骼肌RyR的差异异质性可能反映了钙诱导的钙释放与去极化诱导的Ca 2+释放所需的调制。
The single-channel activity of rabbit skeletal muscle ryanodine receptor (skeletal RyR) and dog cardiac RyR was studied as a function of cytosolic [Ca2+]. The studies reveal that for both skeletal and cardiac RyRs, heterogeneous populations of channels exist, rather than a uniform behavior. Skeletal muscle RyRs displayed two extremes of behavior: 1) low-activity RyRs (LA skeletal RyRs, similar to 35% of the channels) had very low open probability (P-o < 0.1) at all [Ca2+] and remained closed in the presence of Mg2+ (2 mM) and ATP (1 mM); 2) high-activity RyRs (HA skeletal RyRs) had much higher activity and displayed further heterogeneity in their P-o values at low [Ca2+] (0.6) in the presence and absence of Mg2+ and ATP. Heart RyRs were much less sensitive (10X) to inhibition by [Ca2+] than skeletal RyRs. The differential heterogeneity of heart versus skeletal muscle RyRs may reflect the modulation required for calcium-induced calcium release versus depolarization-induced Ca2+ release.