Gardino P F, dos Santos R M, Hokoç J N
Depto. de Farmacologia e Psicobiologia, Universidade do Estado do Rio de Janeiro, Brazil.
Brain Res Dev Brain Res. 1993 Apr 16;72(2):226-36. doi: 10.1016/0165-3806(93)90187-f.
There is a delay from the time when amacrine cells are generated to the time when the dopaminergic phenotype is first expressed, in the chick retina. In order to determine the birthdate of amacrine cells expressing the tyrosine hydroxylase (TH) phenotype, we combined autoradiography of [3H]thymidine incorporated into dividing cells with the immunocytochemical method for TH in mature retinas. We also investigated the morphogenesis and the topographical distribution of dopaminergic amacrine cells using radial and horizontal sections of the chick retina. Although TH immunoreactivity was first detected at E12, the morphological pattern of TH-immunoreactive (TH-IR) amacrine cells started to be defined at E16, with an increasing arborization complexity until hatching. The topographical distribution of dopaminergic cells revealed that TH-IR neurons were predominantly concentrated in the dorsal retina of E13 and E14 embryos. At E18 and PH2 the distribution of dopaminergic cells was uniform throughout the retina. Autoradiography of [3H]thymidine incorporated association with TH immunocytochemistry showed that dopaminergic amacrine cells are generated during a discrete period (E3 through E7) of amacrinogenesis that occurs from E3 to E9. Therefore, a delay of days between histogenesis of dopaminergic amacrine cells and their differentiation is observed.
在鸡视网膜中，从无长突细胞产生到首次表达多巴胺能表型之间存在延迟。为了确定表达酪氨酸羟化酶（TH）表型的无长突细胞的出生日期，我们将掺入分裂细胞中的[3H]胸腺嘧啶核苷的放射自显影与成熟视网膜中TH的免疫细胞化学方法相结合。我们还使用鸡视网膜的径向和水平切片研究了多巴胺能无长突细胞的形态发生和拓扑分布。虽然在胚胎第12天（E12）首次检测到TH免疫反应性，但TH免疫反应性（TH-IR）无长突细胞的形态模式在E16开始形成，其分支复杂性不断增加直至孵化。多巴胺能细胞的拓扑分布显示，TH-IR神经元主要集中在E13和E14胚胎的视网膜背侧。在E18和出生后第2天（PH2），多巴胺能细胞在整个视网膜中的分布是均匀的。[3H]胸腺嘧啶核苷掺入的放射自显影与TH免疫细胞化学相结合表明，多巴胺能无长突细胞是在从E3到E9发生的无长突细胞发生的一个离散时期（E3至E7）产生的。因此，观察到多巴胺能无长突细胞的组织发生与其分化之间存在数天的延迟。
