Fujitsuka N, Kori A A, Sokabe M, Ito F
Department of Physiology, Nagoya University School of Medicine, Japan.
Brain Res. 1988 Mar 8;443(1-2):243-53. doi: 10.1016/0006-8993(88)91618-6.
A preparation of decapsulated muscle spindles with intact sensory innervation has been developed to allow direct access to the sensory terminal for the application of drugs or to alter the extracellular ionic composition. Muscle spindles were isolated from semitendinosus muscles of the frog Rana catesbeiana, and were incubated in a calcium-free Ringer's solution containing 0.2% collagenase. Following optimal incubation at 34 degrees C for 30 min the response pattern of the spindles during stretch could not be distinguished from that of intact spindles, although the duration of individual afferent spikes was prolonged about 4 times normal. The spikes disappeared immediately after the Ringer's solution was replaced with an isotonic choline chloride solution, in contrast to those of intact spindles which remained for 30 min after the replacement. Electron microscopy showed that the outer and inner capsules were partially disrupted. No significant change was observed in the size or packing density of intramembrane particles in freeze-fracture replicas of spindles decapsulated under optimum conditions. More prolonged treatment with the enzyme resulted in abolition of the static component of the response during stretch, and also in an aggregation of the particles, whose size decreased and packing density increased.
已开发出一种具有完整感觉神经支配的去包膜肌梭制剂，以便直接接触感觉末梢来应用药物或改变细胞外离子组成。从牛蛙（Rana catesbeiana）的半腱肌中分离出肌梭，并将其置于含0.2%胶原酶的无钙林格氏液中孵育。在34℃下最佳孵育30分钟后，尽管单个传入冲动的持续时间延长至正常的约4倍，但拉伸期间肌梭的反应模式与完整肌梭无法区分。与完整肌梭在更换溶液后仍持续30分钟不同，当林格氏液被等渗氯化胆碱溶液替代后，冲动立即消失。电子显微镜显示，外膜和内膜部分被破坏。在最佳条件下去包膜的肌梭的冷冻断裂复制品中，膜内颗粒的大小或堆积密度未观察到显著变化。用该酶进行更长时间的处理会导致拉伸期间反应的静态成分消失，还会导致颗粒聚集，其大小减小而堆积密度增加。
