Atomic force microscopy study of the rabbit skeletal muscle ryanodine receptors in different functional states

Atomic force microscope was applied to investigate the effect of extrinsic phospholipid on the structure of rabbit skeletal muscle ryanodine receptor/calcium release channel (RyR1). In addition, in the presence of extrinsic phospholipid, the height and elasticity of the RyR1s in different functional states were also measured. The results indicate: (i) most of the RyR1s showed a normal structure only in the presence of extrinsic phospholipid; (ii) treatment of the RyR1s with AMP and Ca²⁺ together could increase their Young’s Modulus but not change their apparent height; (iii) no detectable change in either height or Young’s Modulus of the RyR1s appeared, if the RyR1s were treated with other activators or inhibitors.     

POTENTIATION OF CAFFEINEINDUCED CONTRACTURE BY RAISING EXTRACELLULAR POTASSIUM IN FROG SKELETAL MUSCLE

用蛙胫前肌小束为材料,研究了提高胞外钾［Ｋ＋］Ｏ对咖啡因挛缩的作用。［Ｋ＋］Ｏ从２ｍｍｏｌ／Ｌ提高到１０或２５ｍｍｏｌ／Ｌ,由３ｍｍｏｌ／Ｌ咖啡因引起的挛缩明显增强。以ＰＫＣ／ＰＣ（ＰＫＣ和ＰＣ分别为在高钾和正常钾条件下的咖啡因挛缩）表示的咖啡因挛缩增强,依赖［Ｋ＋］Ｏ和高钾作用时间。随着１０ｍｍｏｌ／Ｌ［Ｋ＋］Ｏ作用时间延长,直至１０ｍｉｎ,增强逐渐增加。但是,２５ｍｍｏｌ／Ｌ［Ｋ＋］Ｏ作用１ｍｉｎ时增强达到最大,然后下降到对照。ＰＫＣ／ＰＣ变化时程不能用高钾引起的去极化解释,而与由相似［Ｋ＋］Ｏ引起的胞浆自由钙变化时程相符。提示,至少在蛙骨骼肌,高钾引起的咖啡因挛缩增强主要是由胞浆自由钙升高引起的。     

Atomic force microscopy study of the rabbit skeletal muscle ryanodine receptors in different functional states

Atomic force microscope was applied to investigate the effect of extrinsic phospholipid on the structure of rabbit skeletal muscle ryanodine receptor/calcium release channel (RyR1). In addition, in the presence of extrinsic phospholipid, the height and elasticity of the RyR1s in different functional states were also measured. The results indicate: (i) most of the RyR1s showed a normal structure only in the presence of extrinsic phospholipid; (ii) treatment of the RyR1s with AMP and Ca2+ together could increase their Young's Modulus but not change their apparent height; (iii) no detectable change in either height or Young's Modulus of the RyR1s appeared, if the RyR1s were treated with other activators or inhibitors.     

不同功能状态的兔骨骼肌ryanodine受体的原子力显微镜研究

用原子力显微镜观察了外源性磷脂对兔骨骼肌ryanodine受体/钙释放通道(RyR1)结构的影响, 并且测定了有外源性磷脂的RyR1在不同功能状态时高度与弹性的变化. 结果表明: 有外源性磷脂的RyR1能更好地保持其完整的结构; AMP和Ca²⁺共同作用使其Young模量值增加, 而表观高度不变. 但是, 当用其他激动剂或抑制剂作用时, RyR1高度和Young模量值没有显著变化.     

慢性刺激改变正常肌纤维乙酰胆碱敏感区分布的初步观察

交叉神经支配的实验,已为这一观点提供了较为直接的证据,即哺乳动物骨胳肌肌纤维的许多特性是受其运动神经所控制的。但是,神经是怎样控制肌纤维特性的呢?这还是个不清楚的问题。用埋藏电极以模拟慢肌神经冲动发放的频率刺激快肌,或以模拟快肌神经冲动发放的频率刺激慢肌,也可使肌肉的某些特性得到一定程度的改造,使