Senda T, Yu W
Department of Anatomy I, Nagoya University School of Medicine, Japan.
Neurosci Lett. 1999 Feb 26;262(1):69-71. doi: 10.1016/s0304-3940(99)00042-7.
Neurosecretory granules are conveyed along microtubules in the neurohypophysial axon. By both quick-freeze deep-etch and thin section electron microscopies, we found cross-bridges between the granules and microtubules. The length of the cross-bridges (mean 26.6 +/- 15.2 nm) was not uniform, and its histogram was multi-phasic showing the highest peak around 20 nm and several lower peaks in the range of 40-100 nm. This implies that cross-bridges are complexes of several kinds of constituents. Immunofluorescence microscopy showed the expression of a motor protein kinesin in the mouse neurohypophysis. Immunoelectron microscopy detected kinesin at the contact sites of neurosecretory granules to microtubules. These results suggest that kinesin is a major component of the cross-bridges, and involved in the neurosecretory granule transportation.
神经分泌颗粒沿着神经垂体轴突中的微管运输。通过快速冷冻深蚀刻和超薄切片电子显微镜技术，我们发现颗粒与微管之间存在交叉桥。交叉桥的长度（平均26.6 +/- 15.2纳米）并不均匀，其直方图呈多峰状，在20纳米左右出现最高峰，在40 - 100纳米范围内有几个较低的峰。这意味着交叉桥是由几种成分组成的复合物。免疫荧光显微镜显示运动蛋白驱动蛋白在小鼠神经垂体中表达。免疫电子显微镜在神经分泌颗粒与微管的接触部位检测到驱动蛋白。这些结果表明，驱动蛋白是交叉桥的主要成分，并参与神经分泌颗粒的运输。
