PRENATAL TETRODOTOXIN INFUSION BLOCKS SEGREGATION OF RETINOGENICULATE AFFERENTS
PRENATAL TETRODOTOXIN INFUSION BLOCKS SEGREGATION OF RETINOGENICULATE AFFERENTS
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DOI：
10.1126/science.3175636
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发表时间：
1988-10-07
期刊：
影响因子：
56.9
通讯作者：
STRYKER, MP
中科院分区：
文献类型：
--
作者：
SHATZ, CJ;STRYKER, MP
在成年哺乳动物的视觉系统中，来自两只眼睛的神经节细胞轴突在它们的主要目标外侧膝状体核内彼此分离成单独的层。自发产生的动作电位活动在隔离过程中的参与进行了研究，在胎儿期，其中隔离通常发生在猫，胚胎第45天（E45）和出生（E65）之间。阻断电压敏感性钠通道的河豚毒素用于防止动作电位。胎仔在E42接受来自植入子宫内的渗透微型泵的河豚毒素持续颅内输注。输注2周后，眼内注射顺行示踪剂显示河豚毒素阻止分离。对侧投射均匀地充满外侧膝状体核，同侧投射扩大到占据了正常情况下对侧支配的A层的大部分。因此，在胎儿中，早在视觉开始之前，自发的动作电位活动就可能存在于视觉系统中，并有助于视网膜神经通路的分离。
In the adult mammalian visual system, ganglion cell axons from the two eyes are segregated from each other into separate layers within their principal target, the lateral geniculate nucleus. The involvement of spontaneously generated action potential activity in the process of segregation was investigated during the fetal period in which segregation normally occurs in the cat, between embryonic day 45 (E45) and birth (E65). Tetrodotoxin, which blocks the voltage-sensitive sodium channel, was used to prevent action potentials. Fetuses received continuous intracranial infusions of tetrodotoxin from osmotic minipumps implanted in utero on E42. After a 2-week infusion, intraocular injections of anterograde tracers revealed that tetrodotoxin prevented segregation. The contralateral projection filled the lateral geniculate nucleus uniformly, and the ipsilateral projection expanded to occupy most of what would normally be contralaterally innervated layer A. Thus, in the fetus, long before the onset of vision, spontaneous action potential activity is likely to be present in the visual system and to contribute to the segregation of the retinogeniculate pathway.