The KATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers
The KATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers
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DOI：
10.1152/ajpregu.00663.2010
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发表时间：
2011-10-01
影响因子：
2.8
通讯作者：
Renaud, Jean-Marc
中科院分区：
文献类型：
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作者：
Banas, Krystyna;Clow, Charlene;Renaud, Jean-Marc
巴纳斯·K、克洛·C、贾斯敏·BJ、雷诺·JM。糖酵解中的 K-ATP 通道 Kir6.2 亚基含量高于氧化骨骼肌纤维。 Am J Physiol Regul Integr Comp Physiol 301：R916-R925，2011。首次发表于 2011 年 6 月 29 日； doi:10.1152/ajpregu.00663.2010.-长期以来，人们一直认为，在骨骼肌中，ATP 敏感的 K+ 通道 (K-ATP) 通道对于保护能量水平非常重要，而消除其活性会导致纤维损伤并严重损害功能。肌肉和纤维之间对 K-ATP 通道活性缺乏的反应各不相同，其中糖酵解最多的肌纤维受损的严重程度最高。此外，糖酵解肌纤维也比氧化肌纤维更容易面临代谢应激。本研究的目的是确定肌肉和纤维类型之间的 t 管 K-ATP 通道含量是否存在差异。 K-ATP 通道含量使用半定量免疫荧光方法通过用抗 Kir6.2 抗体对比目鱼肌、趾长伸肌 (EDL) 和趾短屈肌 (FDB) 肌肉的横截面进行染色来估计。使用用特定抗肌球蛋白 I、IIA、IIB 和 IIX 抗体染色的连续横截面确定纤维类型。将 Kir6.2 含量的变化与 CaV1.1 含量的变化进行比较，因为该 Ca2+ 通道负责触发肌浆网释放 Ca2+。 Kir6.2含量在氧化比目鱼肌中最低，在糖酵解EDL和FDB中最高。在单个纤维水平上，肌肉内的 Kir6.2 含量顺序为 IIB > IIX > IIA >= I。有趣的是，给定纤维类型的 Kir6.2 含量在比目鱼肌、EDL 和 FDB 之间存在显着差异，并且在 FDB 中最高。 Kir6.2 和 CaV1.1 抗体的相对荧光强度的相关性对于所有三块肌肉都很显着。然而，Kir6.2 的三块肌肉或单个纤维之间的含量变异性比 CaV1.1 大得多。有人认为，随着糖酵解能力的增加和氧化能力的降低，t 管 K-ATP 通道含量增加，并且 K-ATP 通道的表达可能与肌肉/纤维面临代谢应激的频率有关。
Banas K, Clow C, Jasmin BJ, Renaud JM. The K-ATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers. Am J Physiol Regul Integr Comp Physiol 301: R916-R925, 2011. First published June 29, 2011; doi:10.1152/ajpregu.00663.2010.-It has long been suggested that in skeletal muscle, the ATP-sensitive K+ channel (K-ATP) channel is important in protecting energy levels and that abolishing its activity causes fiber damage and severely impairs function. The responses to a lack of K-ATP channel activity vary between muscles and fibers, with the severity of the impairment being the highest in the most glycolytic muscle fibers. Furthermore, glycolytic muscle fibers are also expected to face metabolic stress more often than oxidative ones. The objective of this study was to determine whether the t-tubular K-ATP channel content differs between muscles and fiber types. K-ATP channel content was estimated using a semiquantitative immunofluorescence approach by staining cross sections from soleus, extensor digitorum longus (EDL), and flexor digitorum brevis (FDB) muscles with anti-Kir6.2 antibody. Fiber types were determined using serial cross sections stained with specific antimyosin I, IIA, IIB, and IIX antibodies. Changes in Kir6.2 content were compared with changes in CaV1.1 content, as this Ca2+ channel is responsible for triggering Ca2+ release from sarcoplasmic reticulum. The Kir6.2 content was the lowest in the oxidative soleus and the highest in the glycolytic EDL and FDB. At the individual fiber level, the Kir6.2 content within a muscle was in the order of type IIB > IIX > IIA >= I. Interestingly, the Kir6.2 content for a given fiber type was significantly different between soleus, EDL, and FDB, and highest in FDB. Correlations of relative fluorescence intensities from the Kir6.2 and CaV1.1 antibodies were significant for all three muscles. However, the variability in content between the three muscles or individual fibers was much greater for Kir6.2 than for CaV1.1. It is suggested that the t-tubular K-ATP channel content increases as the glycolytic capacity increases and as the oxidative capacity decreases and that the expression of K-ATP channels may be linked to how often muscles/fibers face metabolic stress.