Lyons Lisa C, Green Charity L, Eskin Arnold
Department of Biology and Biochemistry, University of Houston, Houston, TX, USA.
J Biol Rhythms. 2008 Dec;23(6):538-42. doi: 10.1177/0748730408325359.
Sensitization of the tail-siphon withdrawal reflex in Aplysia, a nonassociative form of learning, affords a superb opportunity to investigate the regulation of learning and memory by the circadian clock. The circadian clock has been shown to modulate long-term but not short-term sensitization. However, no previous studies have examined the role of the circadian clock in intermediate-term memory. Noxious stimulation delivered to the side of the animal using a spaced training protocol resulted in canonical intermediate-term sensitization dependent upon both MAPK signaling and protein synthesis. The authors found that intermediate-term sensitization exhibited strong rhythms in expression in both light-dark cycles and constant darkness. Animals trained during the (subjective) day demonstrated significantly more intermediate-term memory than animals trained at night. Baseline responses prior to training were not modulated by the circadian clock. Thus, these results indicate that the circadian clock strongly modulates intermediate as well as long-term memory.
海兔尾部虹吸式退缩反射的敏感化是一种非联想式学习形式，为研究生物钟对学习和记忆的调节提供了绝佳机会。生物钟已被证明可调节长期而非短期的敏感化。然而，此前尚无研究探讨生物钟在中期记忆中的作用。使用间隔训练方案对动物身体一侧施加有害刺激，会产生典型的中期敏感化，这依赖于丝裂原活化蛋白激酶（MAPK）信号传导和蛋白质合成。作者发现，中期敏感化在明暗周期和持续黑暗条件下均表现出强烈的表达节律。在（主观）白天接受训练的动物表现出的中期记忆明显多于在夜间接受训练的动物。训练前的基线反应不受生物钟调节。因此，这些结果表明生物钟强烈调节中期以及长期记忆。
