Changes during Maturation and Metamorphosis in the Synaptic Organization of the Tadpole Retina Inner Plexiform Layer
Changes during Maturation and Metamorphosis in the Synaptic Organization of the Tadpole Retina Inner Plexiform Layer
复制标题
蝌蚪视网膜内丛状层成熟和变态过程中突触组织的变化
作者：
L. Fisher
电生理学研究表明，不同物种视网膜对视觉信息的处理程度存在较大差异，这显然与物种间的解剖差异有关。在具有复杂接受野的两栖动物和鸟类视网膜中，似乎比具有简单组织的哺乳动物视网膜中有更多的常规（无突起细胞）突触。此外，在复杂视网膜中，串联常规突触的密度更大，其中一个突触前无突过程也是另一个无突过程的突触后密度，这一点尤其显著。带状（双极细胞）突触的密度在不同物种之间保持相当恒定。蝌蚪显然很少利用视觉线索，而成年青蛙则依靠视觉线索生存，这一事实表明，视网膜的电生理和解剖重组发生在变态过程中。这是有证据的。在这里，我报告了在成熟和变态期间以及激素颗粒植入的结果中发现的视网膜突触组织的变化。
ELECTROPHYSIOLOGICAL studies have shown that there is considerable variation in the degree of processing of visual information carried out by the retinas of different species, apparently correlated with anatomical difference between species. In amphibian and avian retinas with complex receptive fields there seem to be more conventional (amacrine cell) synapses than in mammalian retinas with simple organization. Moreover, the greater density of serial-conventional synapses, in which a presynaptic amacrine process is also postsynaptic to another amacrine process, is particularly striking in complex retinas. The density of ribbon (bipolar cell) synapses remains fairly constant from species to species1. The fact that tadpoles apparently make little use of visual cues, whereas adult frogs depend on them for survival, suggests that electrophysiological and anatomical retinal reorganization occurs during metamorphosis. There is some evidence for this2,3. Here I report changes in retinal synaptic organization found in Rana pipiens both during maturation and metamorphosis and as a result of a hormone pellet implantation.