Bertolucci C, Sovrano V A, Magnone M C, Foà A
Dipartimento di Biologia, Università di Ferrara, 44100 Ferrara, Italy.
Am J Physiol Regul Integr Comp Physiol. 2000 Dec;279(6):R2121-31. doi: 10.1152/ajpregu.2000.279.6.R2121.
To establish whether the suprachiasmatic nuclei (SCN) of the Ruin lizard (Podarcis sicula) play a role in entrainment of circadian rhythms to light, we examined the effects of exposure to 24-h light-dark (LD) cycles on the locomotor behavior of lizards with SCN lesions. Lizards became arrhythmic in response to complete SCN lesion under constant temperature and constant darkness (DD), and they remained arrhythmic after exposure to LD cycles. Remnants of SCN tissue in other lesioned lizards were sufficient to warrant entrainment to LD cycles. Hence, the SCN of Ruin lizards are essential both to maintain locomotor rhythmicity and to mediate entrainment of these rhythms to light. We also asked whether light causes expression of Fos-like immunoreactivity (Fos-LI) in the SCN. Under LD cycles, the SCN express a daily rhythm in Fos-LI. Because Fos-LI is undetectable in DD, the rhythm seen in LD cycles is caused by light. We further showed that unilateral SCN lesions in DD induce dramatic period changes. Altogether, the present data support the existence of a strong functional similarity between the SCN of lizards and the SCN of mammals.
为了确定意大利壁蜥（Podarcis sicula）的视交叉上核（SCN）是否在昼夜节律受光照调节的过程中发挥作用，我们研究了暴露于24小时明暗（LD）循环对患有SCN损伤的蜥蜴运动行为的影响。在恒温恒暗（DD）条件下，蜥蜴对完全的SCN损伤会产生节律紊乱，并且在暴露于LD循环后它们仍然保持节律紊乱。其他受损蜥蜴的SCN组织残余足以保证其被LD循环调节。因此，意大利壁蜥的SCN对于维持运动节律以及将这些节律调节至光照条件下都是必不可少的。我们还研究了光照是否会导致SCN中Fos样免疫反应性（Fos-LI）的表达。在LD循环下，SCN中Fos-LI呈现出每日节律。因为在DD条件下检测不到Fos-LI，所以在LD循环中观察到的节律是由光照引起的。我们进一步表明，在DD条件下单侧SCN损伤会导致显著的周期变化。总之，目前的数据支持蜥蜴的SCN与哺乳动物的SCN之间存在很强的功能相似性。
