Li J Y, Jahn R, Dahlström A
Department of Anatomy and Cell Biology, University of Göteborg, Sweden.
Neuroscience. 1994 Dec;63(3):837-50. doi: 10.1016/0306-4522(94)90528-2.
The distribution of synaptotagmin I in the peripheral nervous system of the rat was investigated by immunofluorescence and confocal laser scanning microscopy. After crushing of the sciatic nerve, synaptotagmin I-like immunoreactivity accumulated proximally as well as distally to the crushes in thin and medium-sized axons. Double labelling studies revealed that synaptotagmin I co-localized with tyrosine hydroxylase, a marker of sympathetic adrenergic neurons, and with substance P, a marker for sensory neurons. No synaptotagmin I-like immunoreactivity was found in large axons, while accumulations of the synaptic vesicle proteins synaptophysin and synapsin I were found in all types of axons. Furthermore, no synaptotagmin I-like immunoreactivity was detected in motor endplates. In contrast, the protein was found in muscle spindles of young rats and in perivascular terminals, where it co-localized with synaptophysin and synapsin I. Lumbar sympathectomy resulted in a marked reduction of the amount and intensity of synaptotagmin I-like immunoreactivity in sciatic nerve. High magnification revealed that synaptotagmin I-like immunoreactivity was mainly distributed in a fine granular pattern, but large, brightly fluorescent granules which were not labelled by anti-synaptophysin or anti-synapsin I were occasionally observed. We conclude that synaptotagmin I is mainly expressed in adrenergic and sensory neurons and is absent from, or below detection levels, in motoneurons.
通过免疫荧光和共聚焦激光扫描显微镜研究了大鼠外周神经系统中突触结合蛋白I的分布。坐骨神经挤压后，突触结合蛋白I样免疫反应性在挤压部位近端和远端的细、中型轴突中均有积累。双重标记研究表明，突触结合蛋白I与交感肾上腺素能神经元的标志物酪氨酸羟化酶以及感觉神经元的标志物P物质共定位。在大型轴突中未发现突触结合蛋白I样免疫反应性，而在所有类型的轴突中均发现了突触小泡蛋白突触素和突触结合蛋白I的积累。此外，在运动终板中未检测到突触结合蛋白I样免疫反应性。相反，在幼鼠的肌梭和血管周围终末发现了该蛋白，它与突触素和突触结合蛋白I共定位。腰交感神经切除术导致坐骨神经中突触结合蛋白I样免疫反应性的数量和强度显著降低。高倍放大显示，突触结合蛋白I样免疫反应性主要呈细颗粒状分布，但偶尔也会观察到未被抗突触素或抗突触结合蛋白I标记的大的、明亮荧光颗粒。我们得出结论，突触结合蛋白I主要在肾上腺素能和感觉神经元中表达，在运动神经元中不存在或低于检测水平。
