Carlson C G, Officer T
Department of Physiology, Kirksville College of Osteopathic Medicine, Missouri 63501, USA.
Muscle Nerve. 1996 Sep;19(9):1116-26. doi: 10.1002/(SICI)1097-4598(199609)19:9<1116::AID-MUS6>3.0.CO;2-2.
Single channel events that exhibited the conductance, event duration, and ion selectivity characteristics of calcium leakage activity (CLA) were recorded in association with acetylcholine receptor (AChR) activity in cultured nondystrophic myotubes. The CLA was observed in the presence or absence of acetylcholine (ACh), and at normal or elevated concentrations of calcium. In contrast to results from nondystrophic myotubes, cell-attached patches from several cultured dystrophic (mdx) myotubes exhibited 100% CLA with no AChR activity, even though ACh was present in the pipette solution. Acquisition of an inside-out patch from these membrane areas produced a profound decrease in CLA and the appearance of AChR events exhibiting typical conductance and event duration characteristics. These results suggest that CLA in dystrophic muscle is produced, in part, by unusual physical interactions between AChRs and the dystrophic cytoskeleton that are mediated by the action of intracellular modulators responsible for aggregating and stabilizing AChRs.
在培养的非营养不良性肌管中，记录到与乙酰胆碱受体（AChR）活性相关的单通道事件，这些事件表现出钙泄漏活性（CLA）的电导、事件持续时间和离子选择性特征。在有或没有乙酰胆碱（ACh）的情况下，以及在正常或升高的钙浓度下，都观察到了CLA。与非营养不良性肌管的结果相反，来自几个培养的营养不良性（mdx）肌管的细胞贴附膜片即使移液管溶液中存在ACh，也表现出100%的CLA且没有AChR活性。从这些膜区域获取外翻膜片会使CLA显著降低，并出现表现出典型电导和事件持续时间特征的AChR事件。这些结果表明，营养不良性肌肉中的CLA部分是由AChR与营养不良性细胞骨架之间异常的物理相互作用产生的，这种相互作用由负责聚集和稳定AChR的细胞内调节剂介导。
