Neuronal activity and retrograde intra-axonal transport.

一般认为，突触前神经末梢中的突触小泡与突触前终末膜融合，释放递质。产生的额外末端膜将通过网织蛋白介导的胞饮作用被吸收到末端。因此，突触激活将增加终末被覆小泡的数量，也可能增加沿着轴突逆行运输的小泡的数量。我们试图用鱼雷和纳尔克的电器官的胆碱能神经末梢来澄清这一假设。在刺激电神经的同时，对终末区域进行快速冷冻。电子显微镜下可见突触末梢内有大量突触小泡，但刺激组与对照组无明显差异。我们还观察了神经刺激对轴突逆行运输的影响。用计算机增强的视频图像分析颗粒沿轴突的运动情况。但是，他们的动作并没有受到神经刺激的影响。

It is generally accepted that synaptic vesicles in the pre-synaptic nerve terminal fuse with the presynaptic terminal membrane and release the transmitter. The resulted extra terminal membrane will be uptaken into the terminal by clathrin mediated pinocytosis. Therefore, the synaptic activation will increase the number of coated vesicles in the terminal and also may increase the number of retrogradely transporting vesicles along the axon. We have tried to clarify the assumption using cholinergic nerve terminals of electric organ of Torpedo and Narke. The terminal region was quick-frozen while stimulating the clectric nerve. The replica examined by electron microscopy showed many synaptic vesicles in the terminal, but no significant differences between stimulated one and control. We also examined the retrograde axonal transport upon nerve stimulations. The movement of particles along the axon was analyzed by computer enhanced video image of the interference contrast microscopy of the fine branches of the electric nerve. But, their movements was not modified by stimulation of the nerve.