Hanson E S, Reese B E
Neuroscience Research Institute, University of California, Santa Barbara 93106-5060.
Brain Res Dev Brain Res. 1993 Jun 8;73(2):293-8. doi: 10.1016/0165-3806(93)90150-9.
Following an early retinal lesion, aberrant uncrossed projections from the opposite, undamaged, retina form in the target visual nuclei. The present study has examined the development of such aberrant projections by making retinal lesions in newborn rat pups, and then examining the nature of the uncrossed retinocollicular projection at different ages following the lesion. Intravitreal injections of horseradish peroxidase were made into the intact eye, and the uncrossed projection was subsequently revealed histochemically. A mature aberrant projection forms as early as postnatal day 9. On postnatal days 5 and 2, aberrant projections are discernable amongst the exuberant uncrossed terminals of normal developing rats, although the former have not matured to form the dense terminal fields characteristic of older projections. Aberrant projections were also detectable as early as 12 h following the lesion, revealed as a relative increase in the density of uncrossed label. These results indicate that lesion-induced plastic responses by intact retinal arbors are initiated shortly after the insult, and they caution the use of retinal lesions in studies of normal retinotopic connectivity during development.
在早期视网膜损伤后，来自对侧未受损视网膜的异常未交叉投射会在目标视觉核中形成。本研究通过对新生大鼠幼崽进行视网膜损伤，然后在损伤后的不同年龄检查未交叉的视网膜-丘脑投射的性质，来研究这种异常投射的发育情况。将辣根过氧化物酶玻璃体内注射到未受损的眼睛中，随后通过组织化学方法揭示未交叉的投射。早在出生后第9天就形成了成熟的异常投射。在出生后第5天和第2天，在正常发育大鼠旺盛的未交叉终末中可辨别出异常投射，尽管前者尚未成熟形成 older projections 特有的密集终末场。损伤后12小时即可检测到异常投射，表现为未交叉标记密度的相对增加。这些结果表明，完整视网膜树突的损伤诱导可塑性反应在损伤后不久就开始了，并且它们提醒在发育过程中正常视网膜拓扑连接性研究中使用视网膜损伤时要谨慎。
