Casanovas-Aguilar C, Reblet C, Pérez-Clausell J, Bueno-López J L
Departament de Biologia Cel.lular Animal i Vegetal, Facultat de Biologia, Universitat de Barcelona, Spain.
J Chem Neuroanat. 1998 Aug;15(2):97-109. doi: 10.1016/s0891-0618(98)00035-0.
Infusion of sodium selenite to the occipital cortex of the rat was used for the specific tracing of zinc-rich pathways. Large numbers of labeled somata were found ipsilaterally in the visual, orbital and frontal cortices, and contralaterally in homotopic and heterotopic visual areas. Labeled neurons were also found ipsilaterally in the retrosplenial, parietal, sensory-motor, temporal and perirhinal cortex. In contrast to the cortico-cortical connections, ascending afferents to the visual cortex were not zinc-rich except for a few labeled neurons in the claustrum. Additional injections showed reciprocal zinc-rich connections between the visual cortex and the orbital and frontal cortices. The latter cortices also received ascending zinc-rich afferents from the claustrum. Selenite injections revealed the layered distribution and the morphology of these labeled neurons in the neocortex. Zinc-rich neurons were found in layers II-III, V and VI. However, none was found in layer IV. Zinc-rich somata appeared as pyramidal and inverted neurons. The contrasting chemical properties of cortical and subcortical visual afferents may account for the functional differences between these systems.
向大鼠枕叶皮质注入亚硒酸钠用于特异性追踪富含锌的通路。在同侧的视觉、眶额和额叶皮质发现大量标记的胞体，在对侧的同位和异位视觉区域也发现大量标记的胞体。在同侧的压后皮质、顶叶、感觉运动皮质、颞叶和嗅周皮质也发现了标记的神经元。与皮质-皮质连接不同，除了屏状核中有少数标记神经元外，向视觉皮质的上行传入纤维并不富含锌。额外的注射显示视觉皮质与眶额和额叶皮质之间存在相互的富含锌的连接。后两者皮质也接受来自屏状核的富含锌的上行传入纤维。亚硒酸钠注射揭示了这些标记神经元在新皮质中的分层分布和形态。富含锌的神经元见于第II - III层、第V层和第VI层。然而，在第IV层未发现。富含锌的胞体表现为锥体细胞和倒转神经元。皮质和皮质下视觉传入纤维的化学性质差异可能解释了这些系统之间的功能差异。
