Objective: To evaluate whether the thermotaxis tracking model is suitable for assessing long-term memory (LTM) in the nematode Caenorhabditis elegans.
Methods: Animals were trained at 20 degrees C overnight in presence of food. The percentage of animals performing isothermal tracking (IT) behavior was measured at different time intervals after the training.
Results: The percentage of animals performing IT behavior, the numbers of body bends inside and outside the training temperature, and the expression patterns of AFD and AIY neurons were similar to those in control animals at 36 and 48 h after training; whereas when extending to 60, 72, and 84 h, locomotory behavior defects were observed in the assayed animals, suggesting that this thermal tracking model is feasible for analyzing LTM at 36 and 48 h after training. Moreover, the percentage of animals performing IT behavior was reduced at 18, 36, and 48 h after training in neuronal calcium sensor-1 gene (nsc-1) mutant animals compared with that in wild-type N2 animals. In addition, exposure to plumbum (Pb) significantly repressed the LTM at 18, 36, and 48 h after training in both wild-type N2 and ncs-1 mutant animals.
Conclusion: The thermotaxis tracking model is suitable for evaluating the LTM regulated by NCS-1, and can be employed for elucidating regulatory functions of specific genes or effects of stimuli on memory in C. elegans.
目的: 评价线虫温度趋向性模型是否适用于长时程记忆的研究。
方法: 在 20 °C 含有新鲜食物过夜培养的训练条件下, 考察在不同时间点执行温度趋向性(isothermal tracking, IT)行为的虫体百分比。
结果: 训练后 36 与 48 h, 线虫的 IT 百分数、 温度趋向性模型内外的头部摆动频率、 以及 AFD 和 AIY 神经元的表达模式与对照组相似, 而训练后 60、 72 和 84 h 的线虫则表现出运动行为上的缺陷, 表明温度趋向性模型适合于在训练 36 和 48 h 后的线虫中进行长时程记忆的考察。 此外, 与野生型 N2 相比, 神经元钙传感蛋白(neuronal calcium sensor-1, NCS-1)的突变能够降低训练后 18、 36 和 48 h 的虫体的 IT 百分数。 而铅暴露可以显著抑制训练后 18、 36 和 48 h 野生型和ncs-1突变体动物在不同时间点下的 IT百分数。
结论: 温度趋向性模型适用于评价秀丽线虫中 NCS-1 参与调控的温度感知长时程记忆, 且该模型可用于针对线虫中参与调节或影响记忆行为的某一特定基因或刺激信号功能的揭示。