Redlin U, Mrosovsky N
Department of Zoology, University of Toronto, Ontario, Canada.
J Comp Physiol A. 1999 Apr;184(4):429-37. doi: 10.1007/s003590050342.
The inhibition of locomotion by light (masking) was investigated in Syrian hamsters. When 1-h pulses of light were presented in the early night, activity was strongly suppressed by irradiances of about 1 lx or greater. Ultradian light-dark cycles were used as another way to study masking. Hamsters were unable to entrain to 3.5:3.5-h light-dark cycles, thus permitting the masking and the entraining effects of light to be distinguished. Light had greater suppressive effects on activity in home cages than on activity in novel running wheels. Moreover, in home cages activity remained very low for about 30 min after lights were turned off. Post-pulse suppression of activity was not simply a consequence of reduced running, as shown by experiments in which running was temporarily prevented by locking the wheels. A phase response curve for masking was obtained by placing hamsters in novel wheels for 3-h periods at various times throughout their circadian cycles, and then superimposing a 30-min light pulse. The suppressive effect of light was maximal around the onset of activity, which normally coincides with dusk in hamsters. This may have adaptive value in limiting foraging to the hours of darkness.
在叙利亚仓鼠中研究了光对运动的抑制作用（掩盖效应）。当在傍晚早期给予1小时的光脉冲时，约1勒克斯或更高的辐照度会强烈抑制活动。超日光照-黑暗周期被用作研究掩盖效应的另一种方法。仓鼠无法适应3.5:3.5小时的光照-黑暗周期，因此可以区分光的掩盖效应和夹带效应。与在新颖的跑步轮中的活动相比，光对笼舍中仓鼠活动的抑制作用更强。此外，在笼舍中，关灯后约30分钟活动仍保持在非常低的水平。如通过锁定轮子暂时阻止跑步的实验所示，脉冲后活动的抑制不仅仅是跑步减少的结果。通过在仓鼠昼夜节律周期的不同时间将其置于新颖的轮子中3小时，然后叠加一个30分钟的光脉冲，获得了掩盖效应的相位响应曲线。光的抑制作用在活动开始时最大，这通常与仓鼠的黄昏时间一致。这在将觅食限制在黑暗时间方面可能具有适应性价值。
