Mosko S S, Moore R Y
Brain Res. 1979 Mar 23;164:17-38. doi: 10.1016/0006-8993(79)90003-9.
Previous studies of the effects of suprachiasmatic nucleus (SCN) destruction and visual pathway transections in adult rodents have revealed the primary significance of the SCN and the retinohypothalamic (RH) projection in the generation and entrainment of circadian rhythms. In the present study we found that complete ablation of the SCN in 2-day-old rats, prior to its innervation by the RH projection, permanently eliminates circadian rhythms in spontaneous locomotor activity and drinking; activity and drinking appear randomly distributed over the light-dark cycle. In addition, females exhibit long periods of constant vaginal cornification and an absence of normal estrous cycles. These effects are independent of the animal's visual status; that is, they occur in blinded as well as sighted animals. Incomplete SCN lesions results in partial disruption of rhythmic functions such as damping of circadian rhythms in activity and/or drinking, irregular estrous cycling, and/or complete disruption of only one or two of these measures of rhythmicity. The absence of spared functions after early SCN destruction is consistent with the high degree of specificity for the SCN exhibited by developing RH fibers and further emphasizes the significance of the SCN in circadian rhythm generation. Neither morphological nor functional plasticity has been found following neonatal ablation of the SCN in the rat.
先前对成年啮齿动物视交叉上核（SCN）破坏和视觉通路横断影响的研究表明，SCN和视网膜下丘脑（RH）投射在昼夜节律的产生和同步中具有首要意义。在本研究中，我们发现，在2日龄大鼠的SCN被RH投射支配之前将其完全切除，会永久性消除自发运动活动和饮水的昼夜节律；活动和饮水在明暗周期中呈随机分布。此外，雌性大鼠会出现长时间持续的阴道角化，且缺乏正常的发情周期。这些影响与动物的视觉状态无关；也就是说，在失明和有视力的动物中都会出现。不完全的SCN损伤会导致节律功能部分紊乱，如活动和/或饮水的昼夜节律衰减、发情周期不规则，和/或仅使这些节律性指标中的一两项完全紊乱。早期SCN破坏后不存在保留功能的情况，这与发育中的RH纤维对SCN表现出的高度特异性一致，并进一步强调了SCN在昼夜节律产生中的重要性。在新生大鼠中切除SCN后，未发现形态或功能可塑性。
