Characterization of RyR1-slow, a ryanodine receptor specific to slow-twitch skeletal muscle.
Characterization of RyR1-slow, a ryanodine receptor specific to slow-twitch skeletal muscle.
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RyR1-slow（一种慢肌骨骼肌特异的兰尼碱受体）的表征。
DOI：
10.1152/ajpregu.2000.279.5.r1889
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Block,BA
中科院分区：
文献类型：
--
作者：
Morrissette,J;Xu,L;Nelson,A;Meissner,G;Block,BA
两种不同的骨骼肌ryanodine受体（RyR1s）在鱼类骨骼肌中以纤维类型特异性方式表达（11）。在本研究中，我们比较了鱼类慢抽搐骨骼肌中RyR1-slow与快速抽搐骨骼肌中分离的RyR1-fast和RyR3的[3H]ryanodine结合和单通道活性。Scatchard图显示RyR1-slow与RyR1-fast相比，对[3H]ryanodine的亲和力较低。在单通道记录中，RyR1-slow和RyR1-fast具有相似的斜率电导。然而RyR1-slow的最大打开概率（Po）比RyR1-fast的最大打开概率（Po）小三倍。单通道研究还揭示了金枪鱼快速收缩肌中存在两种ryr种群（RyR1-fast和RyR3）。在所有RyR通道中，RyR3通道的pop最高，并且在毫摩尔Ca2+下表现出较小的抑制作用。在通道中添加5mm Mg-ATP或2.5 mM β，γ-亚甲基腺苷5 ' -三磷酸（AMP-PCP）增加了两种ryr1的Poand [3H]ryanodine结合，但也引起RyR1-slow的Ca2+依赖曲线的移位，从而减弱了Ca2+依赖性失活。[3H]ryanodine结合数据还显示，AMP-PCP的存在降低了Mg2+对RyR1-slow的依赖性抑制。这些结果表明，鱼类慢速和快速抽搐骨骼肌中RyRs的生理特性存在差异，这可能导致这些肌肉类型中细胞内Ca2+调节方式的差异。
Two distinct skeletal muscle ryanodine receptors (RyR1s) are expressed in a fiber type–specific manner in fish skeletal muscle (11). In this study, we compare [3H]ryanodine binding and single channel activity of RyR1-slow from fish slow-twitch skeletal muscle with RyR1-fast and RyR3 isolated from fast-twitch skeletal muscle. Scatchard plots indicate that RyR1-slow has a lower affinity for [3H]ryanodine when compared with RyR1-fast. In single channel recordings, RyR1-slow and RyR1-fast had similar slope conductances. However, the maximum open probability (Po) of RyR1-slow was threefold less than the maximum Poof RyR1-fast. Single channel studies also revealed the presence of two populations of RyRs in tuna fast-twitch muscle (RyR1-fast and RyR3). RyR3 had the highest Poof all the RyR channels and displayed less inhibition at millimolar Ca2+. The addition of 5 mM Mg-ATP or 2.5 mM β,γ-methyleneadenosine 5′-triphosphate (AMP-PCP) to the channels increased the Poand [3H]ryanodine binding of both RyR1s but also caused a shift in the Ca2+dependency curve of RyR1-slow such that Ca2+-dependent inactivation was attenuated. [3H]ryanodine binding data also showed that Mg2+-dependent inhibition of RyR1-slow was reduced in the presence of AMP-PCP. These results indicate differences in the physiological properties of RyRs in fish slow- and fast-twitch skeletal muscle, which may contribute to differences in the way intracellular Ca2+is regulated in these muscle types.