Humlová M, Illnerová H
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Neurosci Res. 1992 Mar;13(2):147-53. doi: 10.1016/0168-0102(92)90095-t.
Adjustment of the circadian clock to shifts in the light/dark (LD) cycle was assessed from the rat pineal N-acetyltransferase (NAT) rhythm which is controlled by a pacemaker in the suprachiasmatic nucleus of the hypothalamus. Re-entrainment to an 8-h delay in the LD cycle took more than 3 days in rats maintained under a regime with 18 h of light and 6 h of darkness per day (LD 18:6) whereas it was completed within 3 days in those maintained under LD 12:12. Re-entrainment to an advance in the LD cycle proceeded through a transient diminution or almost disappearance of the NAT rhythm amplitude following a 5-h, 3-h and even a mere 2-h advance shift under LD 18:6, whereas no such diminution occurred under LD 12:12 even after a 5-h advance shift. Altogether, the data indicate that resetting of the circadian clock after shifts in the LD cycle depends on the photoperiod.
通过大鼠松果体N - 乙酰转移酶（NAT）节律来评估昼夜节律时钟对光/暗（LD）周期变化的调整，该节律受下丘脑视交叉上核中的起搏器控制。在每天光照18小时、黑暗6小时（LD 18:6）的条件下饲养的大鼠，重新适应LD周期延迟8小时需要3天以上，而在LD 12:12条件下饲养的大鼠则在3天内完成。在LD 18:6条件下，分别提前5小时、3小时甚至仅2小时进行移位后，重新适应LD周期提前的过程中，NAT节律振幅会出现短暂减小或几乎消失的情况，而在LD 12:12条件下，即使提前5小时移位，也不会出现这种减小。总之，数据表明，LD周期变化后昼夜节律时钟的重置取决于光周期。
