Lázár G
University of Pécs, Faculty of Medicine, Department of Human Anatomy, 7643 Pécs, Szigeti út 12, Hungary.
Microsc Res Tech. 2001 Aug 15;54(4):201-19. doi: 10.1002/jemt.1133.
Vision is the most important sensory modality to anurans and a great deal of work in terms of hodological, physiological, and behavioral studies has been devoted to the visual system. The aim of this account is to survey data about the distribution of peptides in primary (lateral geniculate complex, pretectum, tectum) and secondary (striatum, anterodorsal and anteroventral tegmental nuclei, isthmic nucleus) visual relay centers. The emphasis is on general traits but interspecies variations are also noted. The smallest amount of peptide-containing neuronal elements was found in the lateral geniculate complex, where primarily nerve fibers showed immunostaining. All peptides found in the lateral geniculate complex, except two, occurred in the pretectum together with four other peptides. A large number of neurons showing intense neuropeptide thyrosine-like immunoreactivity was characteristic here. The mesencephalic tectum was the richest in peptide-like immunoreactive neuronal elements. Almost all peptides investigated were present mainly in fibers, but 9 peptides were found also in cells. The immunoreactive fibers show a complicated overlapping laminar arrangement. Cholecystokinin octapeptide, enkephalins, neuropeptide tyrosine, and substance P (not discussed here) gave the most prominent immunoreactivity. Several peptides also occur in the tectum of fishes, reptiles, birds, and mammals. Peptides in various combinations were found in the striatum, the anterodorsal- and anteroventral tegmental nucleus, and the isthmic nucleus that receive projections from the primary visual centers. The functional significance of peptides in visual information processing is not known. The only exception is neuropeptide tyrosine, which was found to be inhibitory on retinotectal synapses.
视觉是无尾两栖类动物最重要的感觉方式，关于视觉系统，在传导路、生理学和行为学研究方面已经开展了大量工作。本综述的目的是调查肽类在初级视觉中继中心（外侧膝状体复合体、顶盖前区、中脑顶盖）和次级视觉中继中心（纹状体、前背侧和前腹侧被盖核、峡核）中的分布数据。重点在于一般特征，但也会提及种间差异。在外侧膝状体复合体中发现的含肽神经元成分数量最少，主要是神经纤维显示出免疫染色。在外侧膝状体复合体中发现的所有肽类，除了两种之外，在顶盖前区都与其他四种肽类共同存在。这里的一个特征是有大量神经元显示出强烈的神经肽酪氨酸样免疫反应性。中脑顶盖富含肽样免疫反应性神经元成分。几乎所有研究的肽类主要存在于纤维中，但也在细胞中发现了9种肽类。免疫反应性纤维呈现出复杂的重叠分层排列。八肽胆囊收缩素、脑啡肽、神经肽酪氨酸和P物质（此处未讨论）呈现出最显著的免疫反应性。几种肽类也存在于鱼类、爬行类、鸟类和哺乳类动物的顶盖中。在接受来自初级视觉中心投射的纹状体、前背侧和前腹侧被盖核以及峡核中，发现了各种组合的肽类。肽类在视觉信息处理中的功能意义尚不清楚。唯一的例外是神经肽酪氨酸，它被发现对视网膜顶盖突触具有抑制作用。
