Dyck R, Beaulieu C, Cynader M
Department of Ophthalmology, University of British Columbia, Vancouver, Canada.
J Comp Neurol. 1993 Mar 1;329(1):53-67. doi: 10.1002/cne.903290105.
The terminal boutons of many neurons in the telencephalon are known to contain a vesicle-bound, chelatable pool of zinc (Zn2+) that can be selectively visualized with histochemical procedures. In this paper, the normal laminar, areal, and ultrastructural distribution of histochemically reactive zinc in the visual cortex of the adult cat as well as its development from birth are described. In the adult cat visual cortex, intense zinc staining was found in layers I, II, III, and V, with layer VI staining only lightly. The primary geniculostriate input zone, layer IV, was conspicuously distinguished by the relative absence of zinc. This distinct pattern was restricted only to areas 17 and 18 and differentiated them from adjacent cortical area 19 laterally and the subadjacent cingulate cortex. The earliest zinc-positive staining in visual cortical areas 17 and 18 was first apparent by postnatal day 2 (P2) and was characterized by staining of a thin layer at the bottom of the cortical plate. By P10, and continuing through P20, synaptic zinc formed a trilaminar pattern of dense staining in areas 17 and 18, which included the top of layer I, and layers III and V. The laminar pattern of synaptic zinc in visual cortex appeared mature by P30, except that the distribution of zinc in layer IV was not uniform. This was most apparent around P50 in tangential sections through layer IV from opened and flattened cortex, where columnar patches of increased zinc staining were apparent in area 17. These columns were approximately 400 microns in diameter, with a centre-to-centre spacing of approximately 900 microns. The distribution of synaptic zinc apparently reflects the process of synaptic maturity of the cat visual cortex and appears to demarcate a particular form of columnar organization in visual cortex.
已知端脑许多神经元的终末小体含有与囊泡结合的、可螯合的锌（Zn2+）池，可通过组织化学方法选择性地显示出来。本文描述了成年猫视皮层中组织化学反应性锌的正常分层、区域和超微结构分布及其从出生后的发育情况。在成年猫视皮层中，在I、II、III和V层发现强烈的锌染色，VI层染色较浅。初级膝状体纹状输入区IV层明显缺乏锌。这种独特的模式仅局限于17和18区，将它们与外侧相邻的19区皮质和相邻的扣带回皮质区分开来。视皮层17和18区最早的锌阳性染色在出生后第2天（P2）首次明显出现，其特征是皮质板底部的薄层染色。到P10，并持续到P20，突触锌在17和18区形成了三层密集染色模式，包括I层顶部以及III和V层。视皮层中突触锌的分层模式在P30时似乎成熟，只是IV层中锌的分布不均匀。这在从打开并展平的皮质切取的IV层切线切片中，在P50左右最为明显，此时17区可见锌染色增加的柱状斑块。这些柱直径约400微米，中心间距约900微米。突触锌的分布显然反映了猫视皮层的突触成熟过程，似乎划分了视皮层中一种特殊形式的柱状组织。
