Aonuma Hitoshi, Totani Yuki, Kaneda Mugiho, Nakamura Ryota, Watanabe Takayuki, Hatakeyama Dai, Dyakonova Varvara E, Lukowiak Ken, Ito Etsuro
Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 060-0811, Japan; CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
Department of Biology, Waseda University, Shinjuku, Tokyo 162-8480, Japan.
Neurobiol Learn Mem. 2018 Feb;148:20-29. doi: 10.1016/j.nlm.2017.12.010. Epub 2017 Dec 30.
The pond snail Lymnaea stagnalis learns conditioned taste aversion (CTA) and consolidates it into long-term memory (LTM). How well they learn and form memory depends on the degree of food deprivation. Serotonin (5-HT) plays an important role in mediating feeding, and insulin enhances the memory consolidation process following CTA training. However, the relationship between these two signaling pathways has not been addressed. We measured the 5-HT content in the central nervous system (CNS) of snails subjected to different durations of food deprivation. One-day food-deprived snails, which exhibit the best learning and memory, had the lowest 5-HT content in the CNS, whereas 5-day food-deprived snails, which do not learn, had a high 5-HT content. Immersing 1-day food-deprived snails in 5-HT impaired learning and memory by causing an increase in 5-HT content, and that the injection of insulin into these snails reversed this impairment. We conclude that insulin rescues the CTA deficit and this may be due to a decrease in the 5-HT content in the CNS of Lymnaea.
椎实螺能学会条件性味觉厌恶（CTA）并将其巩固为长期记忆（LTM）。它们学习和形成记忆的能力取决于饥饿程度。血清素（5-HT）在介导进食过程中起重要作用，胰岛素可增强CTA训练后的记忆巩固过程。然而，这两条信号通路之间的关系尚未得到研究。我们测量了经历不同时长饥饿的蜗牛中枢神经系统（CNS）中的5-HT含量。饥饿一天的蜗牛学习和记忆能力最佳，其CNS中的5-HT含量最低，而饥饿五天的蜗牛不具备学习能力，其5-HT含量较高。将饥饿一天的蜗牛浸泡在5-HT中会导致5-HT含量增加，从而损害学习和记忆能力，而向这些蜗牛注射胰岛素可逆转这种损害。我们得出结论，胰岛素可挽救CTA缺陷，这可能是由于椎实螺CNS中5-HT含量降低所致。
