Nakai Junko, Chikamoto Nozomi, Fujimoto Kanta, Totani Yuki, Hatakeyama Dai, Dyakonova Varvara E, Ito Etsuro
Department of Biology, Waseda University, Tokyo, Japan.
Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan.
Front Behav Neurosci. 2022 Apr 26;16:882932. doi: 10.3389/fnbeh.2022.882932. eCollection 2022.
Insulin and insulin-like peptides (ILP) help to maintain glucose homeostasis, whereas insulin-like growth factor (IGF) promotes the growth and differentiation of cells in both vertebrates and invertebrates. It is sometimes difficult to distinguish between ILP and IGF in invertebrates, however, because in some cases ILP has the same function as IGF. In the present review, therefore, we refer to these peptides as ILP/IGF signaling (IIS) in invertebrates, and discuss the role of IIS in memory formation after classical conditioning in invertebrates. In the arthropod , IIS is involved in aversive olfactory memory, and in the nematode , IIS controls appetitive/aversive response to NaCl depending on the duration of starvation. In the mollusk , IIS has a critical role in conditioned taste aversion. Insulin in mammals is also known to play an important role in cognitive function, and many studies in humans have focused on insulin as a potential treatment for Alzheimer's disease. Although analyses of tissue and cellular levels have progressed in mammals, the molecular mechanisms, such as transcriptional and translational levels, of IIS function in cognition have been far advanced in studies using invertebrates. We anticipate that the present review will help to pave the way for studying the effects of insulin, ILPs, and IGFs in cognitive function across phyla.
胰岛素和胰岛素样肽（ILP）有助于维持葡萄糖稳态，而胰岛素样生长因子（IGF）在脊椎动物和无脊椎动物中均促进细胞的生长和分化。然而，在无脊椎动物中有时很难区分ILP和IGF，因为在某些情况下ILP具有与IGF相同的功能。因此，在本综述中，我们将这些肽称为无脊椎动物中的ILP/IGF信号传导（IIS），并讨论IIS在无脊椎动物经典条件反射后记忆形成中的作用。在节肢动物中，IIS参与厌恶嗅觉记忆，而在线虫中，IIS根据饥饿持续时间控制对NaCl的食欲/厌恶反应。在软体动物中，IIS在条件性味觉厌恶中起关键作用。哺乳动物中的胰岛素在认知功能中也起着重要作用，许多针对人类的研究都将胰岛素作为治疗阿尔茨海默病的潜在药物。尽管在哺乳动物中组织和细胞水平的分析已经取得进展，但在使用无脊椎动物的研究中，IIS在认知中的功能的分子机制，如转录和翻译水平，已经取得了很大进展。我们预计本综述将有助于为研究胰岛素、ILP和IGF在跨门认知功能中的作用铺平道路。
