Sugita S, Minematsu M, Nagai K, Sugahara K
Department of Animal Science, Faculty of Agriculture, Utsunomiya University, Tochigi, Japan.
Exp Anim. 1996 Apr;45(2):115-24. doi: 10.1538/expanim.45.115.
Analysis of circadian locomotor activity, Golgi-Cox impregnation, and immunohistochemistry were studied on the hereditary microphthalmic rat which congenitally lacked the optic nerve. These blind rats showed free-running circadian rhythms in their locomotor activities. Both the normal and microphthalmic rats had similar ultradian rhythms in addition to circadian rhythms. The neuronal cell population and volume of the hypothalamic suprachiasmatic nucleus (SCN) of the microphthalmic rats were 66% and 71% of those in normal rats, respectively. The number of SCN neurons containing vasoactive intestinal peptide-like immunoreactive substance was dramatically decreased to 35% of that in normal rats. Golgi-Cox impregnation revealed that three types of neurons in the SCN of the microphthalmic rats were consistently distinguished as observed in normal rats. Although there were no changes in the numbers of primary dendrites of the SCN neurons in the microphthalmic and normal rats, the number of secondary and tertiary dendrites in the SCN of the microphthalmic rats was smaller than that of normal rats. These observations suggest that the retinal input may be important for normal morphological formation of the SCN during development, but not for the generation of circadian rhythms and ultradian rhythms.
对先天性缺乏视神经的遗传性小眼大鼠进行了昼夜节律性运动活动分析、高尔基-考克斯染色法及免疫组织化学研究。这些失明大鼠在运动活动中表现出自由运行的昼夜节律。正常大鼠和小眼大鼠除昼夜节律外，还具有相似的超日节律。小眼大鼠下丘脑视交叉上核（SCN）的神经元细胞数量和体积分别为正常大鼠的66%和71%。含有血管活性肠肽样免疫反应物质的SCN神经元数量显著减少至正常大鼠的35%。高尔基-考克斯染色显示，小眼大鼠SCN中的三种神经元类型与正常大鼠中观察到的一致。尽管小眼大鼠和正常大鼠SCN神经元的初级树突数量没有变化，但小眼大鼠SCN中二级和三级树突的数量比正常大鼠少。这些观察结果表明，视网膜输入可能对发育过程中SCN的正常形态形成很重要，但对昼夜节律和超日节律的产生并不重要。
