Wong-Riley M T, Trusk T C, Kaboord W, Huang Z
Department of Cellular Biology and Anatomy, Medical College of Wisconsin, Milwaukee, 53226.
J Neurocytol. 1994 Sep;23(9):533-53. doi: 10.1007/BF01262055.
One of the hallmarks of the primate striate cortex is the presence of cytochrome oxidase-rich puffs in its supragranular layers. Neurons in puffs have been classified as type A, B, and C in ascending order of cytochrome oxidase content, with type C cells being the most vulnerable to retinal impulse blockade. The present study aimed at analysing cytochrome oxidase-poor interpuffs with reference to their metabolic cell types and the effect of intraretinal tetrodotoxin treatment. The same three metabolic types were found in interpuffs, except that type B and C neurons were smaller and less cytochrome oxidase-reactive in interpuffs than in puffs. Type A neurons had small perikarya, low levels of cytochrome oxidase, and received exclusively symmetric axosomatic synapses. The largest neurons were pyramidal, type B cells with moderate cytochrome oxidase activity and were also contacted exclusively by symmetric axosomatic synapses. Type C cells medium-sized with a rich supply of large, darkly reactive mitochondria and possessed all the characteristics of GABAergic neurons. They were the only cell type that received both symmetric and asymmetric axosomatic synapses. Two weeks of monocular tetrodotoxin blockade in adult monkeys caused all three major cell types in deprived interpuffs to suffer a significant downward shift in the size and cytochrome oxidase reactivity of their mitochondria, but the effects were more severe in type B and C neurons. In nondeprived interpuffs, all three cell types gained both in size and absolute number of mitochondria, and type A cells also had an elevated level of cytochrome oxidase, indicating that they might be functioning at a competitive advantage over cells in deprived columns. However, type B and C neurons showed a net loss of darkly reactive mitochondria, indicating that these cells became less active. Thus, mature interpuff neurons remained vulnerable to retinal impulse blockade and the metabolic capacity of these cells remains tightly regulated by neuronal activity.
灵长类动物纹状皮质的一个显著特征是其颗粒上层中存在富含细胞色素氧化酶的斑。斑中的神经元根据细胞色素氧化酶含量的升序被分类为A、B和C型，其中C型细胞对视网膜冲动阻断最为敏感。本研究旨在分析细胞色素氧化酶含量低的斑间区，涉及它们的代谢细胞类型以及视网膜内注射河豚毒素治疗的效果。在斑间区发现了相同的三种代谢类型，只是B型和C型神经元在斑间区比在斑中更小且细胞色素氧化酶反应性更低。A型神经元有小的胞体，细胞色素氧化酶水平低，并且仅接受对称的轴体突触。最大的神经元是锥体状的B型细胞，具有中等的细胞色素氧化酶活性，也仅被对称的轴体突触所接触。C型细胞中等大小，有大量深色反应性线粒体供应，具有GABA能神经元的所有特征。它们是唯一接受对称和不对称轴体突触的细胞类型。成年猴子单眼河豚毒素阻断两周导致剥夺侧斑间区的所有三种主要细胞类型的线粒体大小和细胞色素氧化酶反应性显著下降，但对B型和C型神经元的影响更严重。在未剥夺侧的斑间区，所有三种细胞类型的线粒体大小和绝对数量都增加了，并且A型细胞的细胞色素氧化酶水平也升高，表明它们可能比剥夺柱中的细胞具有竞争优势。然而，B型和C型神经元深色反应性线粒体出现净损失，表明这些细胞变得不那么活跃。因此成熟的斑间区神经元仍然对视网膜冲动阻断敏感，并且这些细胞的代谢能力仍然受到神经元活动的严格调节。
