Dallmann R, Mrosovsky N
Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA.
Behav Brain Res. 2007 Jun 18;180(2):197-202. doi: 10.1016/j.bbr.2007.03.006. Epub 2007 Mar 14.
Recently, it has been reported that mice deficient for Dexras1 have a diminished phase-shifting response to photic stimuli but an enhanced response to non-photic stimuli; the latter is of additional interest in that mice generally show relatively weak and unreliable responses to non-photic events. Therefore, in situations in which both photic and non-photic stimuli are present, control of circadian rhythms, relative to wild-types, should tip toward non-photic stimuli in Dexras1(-/-) mice. However, we detected no differences in an experiment in which photic and non-photic entraining agents were presented 180 degrees out of phase, i.e. were in conflict with each other. Furthermore, Dexras1(-/-) and wild-type mice did not differ in non-photic phase shifting to a pulse of confinement in a novel running wheel. Suppression of locomotion by light (masking effect) did not differ between the genotypes, indicating that the photoreceptor input to the non-image forming system is intact. The circadian phenotype of Dexras1(-/-) mice appears to be more complicated than previously thought.
最近有报道称，缺乏Dexras1的小鼠对光刺激的相位转移反应减弱，但对非光刺激的反应增强；后者更值得关注，因为小鼠通常对非光事件表现出相对较弱且不可靠的反应。因此，在同时存在光刺激和非光刺激的情况下，相对于野生型小鼠，Dexras1(-/-)小鼠的昼夜节律控制应更倾向于非光刺激。然而，在一个实验中，我们未检测到差异，该实验中光刺激和非光刺激的同步因子呈现出180度的相位差，即相互冲突。此外，Dexras1(-/-)小鼠和野生型小鼠在新的跑步轮中对禁闭脉冲的非光相位转移方面没有差异。光对运动的抑制（掩蔽效应）在不同基因型之间没有差异，这表明非成像系统的光感受器输入是完整的。Dexras1(-/-)小鼠的昼夜节律表型似乎比之前认为的更为复杂。
