O'Leary D D, Crespo D, Fawcett J W, Cowan W M
Brain Res. 1986 Nov;395(1):96-103. doi: 10.1016/s0006-8993(86)80014-2.
We have examined the effects of blocking retinal ganglion cell activity with the sodium channel blocker tetrodotoxin (TTX) on the postnatal reduction in the number of optic nerve axons (and, by interference, the degree of ganglion cell loss in the retina). TTX was injected every other day into the left eyes of a series of albino rats beginning on the day of birth, continuing through the 3rd, 7th, 12th or 14th days when the animals were killed and the optic nerves from both eyes were prepared for electron microscopy. The numbers of axons in the TTX treated and untreated optic nerves from the opposite side were determined from electron micrographs, and compared to the number seen in normal rats at the same ages. Both the magnitude and the time course of the reduction in the number of axons in the TTX-treated and untreated nerves were found to be similar to those seen in normal animals. However, there was a slight reduction in the loss of optic axons in the untreated nerves on the side opposite the TTX injections; this attenuation in axon loss could be mimicked by large systemic injections of TTX, and is probably attributable to a general systemic effect following repeated intraocular injections. These findings indicate that blocking ganglion cell activity with intraocular injections of TTX has little effect on the normal rate of axon loss from the optic nerve and on the numbers of ganglion cells that die during the first two weeks of postnatal life.
我们研究了用钠通道阻滞剂河豚毒素（TTX）阻断视网膜神经节细胞活性对出生后视神经轴突数量减少的影响（以及通过干扰，对视网膜中神经节细胞损失程度的影响）。从出生当天开始，每隔一天向一系列白化大鼠的左眼注射TTX，持续到第3、7、12或14天，此时处死动物，并将双眼的视神经制备用于电子显微镜检查。从电子显微镜照片中确定经TTX处理和未处理的对侧视神经中的轴突数量，并与相同年龄正常大鼠中的轴突数量进行比较。发现经TTX处理和未处理的神经中轴突数量减少的幅度和时间进程与正常动物中观察到的相似。然而，在TTX注射对侧未处理的神经中，视神经轴突的损失略有减少；这种轴突损失的减弱可以通过大剂量全身注射TTX来模拟，并且可能归因于反复眼内注射后的一般全身效应。这些发现表明，眼内注射TTX阻断神经节细胞活性对视神经轴突正常损失率以及出生后前两周死亡的神经节细胞数量几乎没有影响。
