Dunaevsky A, Connor E A
Department of Biology, University of Massachusetts, Amherst 01003, USA.
J Neurosci. 1995 Sep;15(9):6137-44. doi: 10.1523/JNEUROSCI.15-09-06137.1995.
Here we have investigated the role of the muscle fiber in the maintenance of presynaptic function at frog motor nerve terminals. Muscle fibers were selectively damaged and prevented from regenerating while leaving the motor innervation intact. Presynaptic activity of the resulting target-deprived nerve terminals was assayed using the fluorescent dye, FM1-43. FM1-43 stains nerve terminals in an activity-dependent fashion in that it incorporates into synaptic vesicles and can be released upon stimulation. We demonstrate that nerve terminals permanently deprived of target for 1 to 5 months maintain the ability to release and recycle synaptic vesicles in response to stimulation. The level of presynaptic function of target-deprived nerve terminals was not detectably different from that of nerve terminals in contact with muscle fibers. The remarkable maintenance of presynaptic function in these target-deprived nerve terminals indicates that the molecular machinery required for vesicular release is maintained in a functional state for long periods without target muscle fibers.
在此，我们研究了肌纤维在维持青蛙运动神经末梢突触前功能中的作用。我们选择性地损伤肌纤维并阻止其再生，同时保持运动神经支配完整。使用荧光染料FM1-43检测由此产生的靶剥夺神经末梢的突触前活性。FM1-43以活动依赖的方式对神经末梢进行染色，因为它可掺入突触小泡并在受到刺激时释放。我们证明，永久性剥夺靶标1至5个月的神经末梢仍保持响应刺激释放和循环利用突触小泡的能力。靶剥夺神经末梢的突触前功能水平与接触肌纤维的神经末梢相比，没有明显差异。这些靶剥夺神经末梢突触前功能的显著维持表明，囊泡释放所需的分子机制在没有靶标肌纤维的情况下可长期保持功能状态。
