Mrosovsky N, Salmon P A
Department of Zoology, University of Toronto, Ontario, Canada.
Nature. 1987;330(6146):372-3. doi: 10.1038/330372a0.
The idea of ameliorating jetlag with drugs has received considerable attention. Melatonin has been found to reduce feelings of jetlag in people after transatlantic flights. In hamsters, injections of triazolam, a benzodiazepine, increase the rate of adjustment of activity rhythms to an 8 h advance of the light-dark (LD) cycle. But melatonin can make people drowsy and triazolam often induces hamsters to run in their wheels. Therefore, it is not clear whether these chemicals exert their chronotypic effects by acting directly on circadian pacemakers or because they first alter behavioural states. Non-photic behavioural events (for instance, social interactions) are capable of entraining rhythms and causing phase shifts. Thus, it is possible that behavioural events alone could alter the rate of adjustment to new LD cycles. To investigate this possibility, we studied the rate of re-entrainment of hamsters in a testing paradigm similar to that used with triazolam. We found that the rate of adjustment could be more than doubled simply by making the animals active on a single occasion in the middle of their normal rest period, immediately after the shift in the LD cycle.
用药物改善时差反应的想法已受到广泛关注。褪黑素已被发现可减轻人们跨大西洋飞行后的时差反应。在仓鼠身上，注射三唑仑（一种苯二氮䓬类药物）可提高其活动节律对明暗（LD）周期提前8小时的调整速率。但褪黑素会使人困倦，三唑仑常常会诱导仓鼠在转轮中跑动。因此，尚不清楚这些化学物质是直接作用于昼夜节律起搏器发挥其对时型的影响，还是因为它们首先改变了行为状态。非光性行为事件（例如社交互动）能够调节节律并引起相位偏移。因此，仅行为事件就有可能改变对新LD周期的调整速率。为了研究这种可能性，我们在一种类似于对三唑仑所采用的测试范式中，研究了仓鼠的重新调整速率。我们发现，仅通过在正常休息期中间、LD周期转变后立即让动物有一次活动，调整速率就能增加一倍多。
