Schmidt-Kastner R, Meller D, Eysel U T
Department of Neurophysiology, Medical Faculty, Ruhr-Universität Bochum, Germany.
Exp Neurol. 1992 Sep;117(3):230-46. doi: 10.1016/0014-4886(92)90132-a.
The neuron-specific calcium-binding proteins, parvalbumin and calbindin-D-28k, were studied in the subcortical visual system of normal and unilaterally deafferented albino rats. Immunohistochemistry with monoclonal antibodies was used on vibratome sections through optic tract (OT), dorsal lateral geniculate nucleus (dLGN), olivary pretectal nucleus (OPN), and superior colliculus (SC). In controls, OT stained strongly for parvalbumin and weakly for calbindin-D-28k. The dLGN contained a plexus of parvalbumin-positive fibers. In dLGN, calbindin-D-28k-antibodies showed strong labeling of some neurons with long dendrites and weak staining of the cytoplasm in other neurons. In OPN, parvalbumin stained a ring of neurons and terminals in the shell region, whereas calbindin-D-28k was contained in medial cell populations. In SC, parvalbumin was contained in fibers, terminals, and neurons throughout the visual layer. Calbindin-D-28k showed a laminar distribution of neurons with a predominance in deep portions of superficial grey matter and in ventral portions of stratum opticum. Following unilateral deafferentation induced by optic nerve section, retinal axons showed immunohistochemical changes related to Wallerian degeneration and target neurons reacted by changes of calcium-binding proteins. Parvalbumin and calbindin-D-28k immunostaining decreased during Wallerian degeneration of OT. In the deafferented dLGN, immunohistochemical labeling for calbindin-D-28k declined in strongly stained neurons from 4 to 21 days after lesion. Measurement of dendritic length per number of cells or per area of dLGN showed a significant decline for the contralateral side at 4, 8, and 21 days (ANOVA, P less than 0.05). In deafferented OPN, terminal-like staining for parvalbumin decreased and neuronal labeling was enhanced. In deafferented SC, the neuronal and dendritic staining for parvalbumin increased beginning from Day 1 on and persisting at Day 21, whereas fibers and terminal-like elements decreased in staining. Measurement of parvalbumin-positive neurons per area of SC showed a significant increase of labeling in the contralateral side from Day 1 to Day 21 (ANOVA, P less than 0.05). These studies show that cellular responses to deafferentation of visual neurons involve a regulation of calcium-binding proteins. The decline in staining for calbindin-D-28k in dLGN may relate to reduced retinal afferent activity. The progressive cellular changes in parvalbumin staining may be related to unmasking of intrinsic neurons after removal of parvalbumin-containing, afferent fibers and terminals. Additionally, the changes of parvalbumin labeling in SC neurons may reflect a plastic reorganization of local circuits known to occur in rat SC in response to deafferentation.
在正常和单侧去传入的白化大鼠的皮质下视觉系统中，研究了神经元特异性钙结合蛋白小白蛋白和钙结合蛋白-D-28k。通过视神经束（OT）、背外侧膝状核（dLGN）、橄榄顶盖前核（OPN）和上丘（SC）的振动切片，使用单克隆抗体进行免疫组织化学研究。在对照组中，OT对小白蛋白染色强烈，对钙结合蛋白-D-28k染色较弱。dLGN含有小白蛋白阳性纤维丛。在dLGN中，钙结合蛋白-D-28k抗体对一些具有长树突的神经元显示出强烈标记，而对其他神经元的细胞质染色较弱。在OPN中，小白蛋白在壳区域的神经元和终末环处染色，而钙结合蛋白-D-28k存在于内侧细胞群中。在SC中，小白蛋白存在于整个视觉层的纤维、终末和神经元中。钙结合蛋白-D-28k显示神经元呈层状分布，在浅表灰质的深部和视层的腹侧部分占优势。在视神经切断诱导的单侧去传入后，视网膜轴突显示出与华勒变性相关的免疫组织化学变化，靶神经元通过钙结合蛋白的变化做出反应。在OT的华勒变性过程中，小白蛋白和钙结合蛋白-D-28k免疫染色减少。在去传入的dLGN中，损伤后4至21天，钙结合蛋白-D-28k的免疫组织化学标记在强染色神经元中下降。测量dLGN中每个细胞或每单位面积的树突长度，发现对侧在4、8和21天时显著下降（方差分析，P<0.05）。在去传入的OPN中，小白蛋白的终末样染色减少，神经元标记增强。在去传入的SC中，小白蛋白的神经元和树突染色从第1天开始增加并持续到第21天，而纤维和终末样成分的染色减少。测量SC每单位面积的小白蛋白阳性神经元，发现对侧从第1天到第21天标记显著增加（方差分析，P<0.05）。这些研究表明，视觉神经元对去传入的细胞反应涉及钙结合蛋白的调节。dLGN中钙结合蛋白-D-28k染色的下降可能与视网膜传入活动减少有关。小白蛋白染色的渐进性细胞变化可能与去除含小白蛋白的传入纤维和终末后内在神经元的暴露有关。此外，SC神经元中小白蛋白标记的变化可能反映了大鼠SC中已知的局部回路在去传入后发生的可塑性重组。
