de la Cruz R R, Pastor A M, Martińez-Guijarro F J, López-García C, Delgado-García J M
Laboratorio de Neurociencia, Facultad de Biología, Universidad de Sevilla, Spain.
J Comp Neurol. 1998 Jan 19;390(3):377-91. doi: 10.1002/(sici)1096-9861(19980119)390:3<377::aid-cne6>3.0.co;2-z.
Calcium-binding proteins have been shown to be excellent markers of specific neuronal populations. We aimed to characterize the expression of calcium-binding proteins in identified populations of the cat extraocular motor nuclei by means of immunohistochemistry against parvalbumin, calretinin, and calbindin D-28k. Abducens, medial rectus, and trochlear motoneurons were retrogradely labeled with horseradish peroxidase from their corresponding muscles. Oculomotor and abducens internuclear neurons were retrogradely labeled after horseradish peroxidase injection into either the abducens or the oculomotor nucleus, respectively. Parvalbumin staining produced the highest density of immunoreactive terminals in all extraocular motor nuclei and was distributed uniformly. Around 15-20% of the motoneurons were moderately stained with antibody against parvalbumin, but their axons were heavily stained, indicating an intracellular segregation of parvalbumin. Colchicine administration increased the number of parvalbumin-immunoreactive motoneurons to approximately 85%. Except for a few calbindin-immunoreactive trochlear motoneurons (1%), parvalbumin was the only marker of extraocular motoneurons. Oculomotor internuclear neurons identified from the abducens nucleus constituted a nonuniform population, because low percentages of the three types of immunostaining were observed, calbindin being the most abundant (28.5%). Other interneurons located within the boundaries of the oculomotor nucleus were mainly calbindin-immunoreactive. The medial longitudinal fascicle contained numerous parvalbumin- and calretinin-immunoreactive but few calbindin-immunoreactive axons. The majority of abducens internuclear neurons projecting to the oculomotor nucleus (80.7%) contained calretinin. Moreover, the distribution of calretinin-immunoreactive terminals in the oculomotor nucleus overlapped that of the medial rectus motoneurons and matched the anterogradely labeled terminal field of the abducens internuclear neurons. Parvalbumin immunostained 42% of the abducens internuclear neurons. Colocalization of parvalbumin and calretinin was demonstrated in adjacent semithin sections, although single-labeled neurons were also observed. Therefore, calretinin is proven to be a good marker of abducens internuclear neurons. From all of these data, it is concluded that parvalbumin, calretinin, and calbindin D-28k selectively delineate certain neuronal populations in the oculomotor system and constitute valuable tools for further analysis of oculomotor function under normal and experimental conditions.
钙结合蛋白已被证明是特定神经元群体的优良标志物。我们旨在通过针对小白蛋白、钙视网膜蛋白和钙结合蛋白D - 28k的免疫组织化学方法，来表征猫眼外肌运动核中已确定群体的钙结合蛋白表达情况。展神经、内直肌和滑车神经运动神经元用辣根过氧化物酶从其相应肌肉进行逆行标记。动眼神经和展神经的核间神经元在分别向展神经核或动眼神经核注射辣根过氧化物酶后进行逆行标记。小白蛋白染色在所有眼外肌运动核中产生了最高密度的免疫反应性终末，且分布均匀。约15 - 20%的运动神经元被抗小白蛋白抗体中度染色，但其轴突被重度染色，表明小白蛋白存在细胞内分隔。秋水仙碱给药使小白蛋白免疫反应性运动神经元数量增加至约85%。除了少数钙结合蛋白免疫反应性滑车神经运动神经元（1%）外，小白蛋白是眼外肌运动神经元的唯一标志物。从展神经核鉴定出的动眼神经核间神经元构成了一个不均匀的群体，因为观察到三种免疫染色类型的比例较低，其中钙结合蛋白最为丰富（28.5%）。位于动眼神经核边界内的其他中间神经元主要是钙结合蛋白免疫反应性的。内侧纵束包含大量小白蛋白和钙视网膜蛋白免疫反应性轴突，但钙结合蛋白免疫反应性轴突较少。投射到动眼神经核的展神经核间神经元大多数（80.7%）含有钙视网膜蛋白。此外，钙视网膜蛋白免疫反应性终末在动眼神经核中的分布与内直肌运动神经元的分布重叠，且与展神经核间神经元的顺行标记终末野匹配。小白蛋白免疫染色了42%的展神经核间神经元。在相邻的半薄切片中证实了小白蛋白和钙视网膜蛋白的共定位，尽管也观察到了单标记神经元。因此，钙视网膜蛋白被证明是展神经核间神经元的良好标志物。从所有这些数据可以得出结论，小白蛋白、钙视网膜蛋白和钙结合蛋白D - 28k选择性地描绘了动眼神经系统中的某些神经元群体，并构成了在正常和实验条件下进一步分析动眼神经功能的有价值工具。
