Ito E, Okada R, Sakamoto Yuki, Otshuka Emi, Mita K, Okuta Akiko, Sunada H, Sakakibara M
Laboratory of Functional Biology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Japan.
Acta Biol Hung. 2012;63 Suppl 2:194-201. doi: 10.1556/ABiol.63.2012.Suppl.2.25.
The pond snail, Lymnaea stagnalis, is capable of learning conditioned taste aversion (CTA) and consolidating this CTA into long-term memory (LTM). The DNA microarray experiments showed that some of molluscan insulin-related peptides (MIPs) were up-regulated in snails exhibiting CTA-LTM. On the other hand, the electrophysiological experiments showed that application of secretions from the MIPs-containing cells evoked long-term potentiation (LTP) at the synapses between the cerebral giant cell (a key interneuron for CTA) and the B1 motoneuron (a buccal motoneuron). We thus hypothesized that MIPs and MIP receptors play an important role at the synapses, probably underlying the CTA-LTM consolidation process. To examine this hypothesis, we applied the antibody, which recognizes the binding site of mammalian insulin receptors and is thought to cross-react MIP receptors, to the Lymnaea CNS. Our present data showed that an application of the antibody for insulin receptors to the isolated CNS blocked LTP, and that an injection of the antibody into the Lymnaea abdominal cavity inhibited LTM consolidation, but not CTA formation.
椎实螺（Lymnaea stagnalis）能够学习条件性味觉厌恶（CTA）并将这种CTA巩固为长期记忆（LTM）。DNA微阵列实验表明，一些软体动物胰岛素相关肽（MIPs）在表现出CTA-LTM的蜗牛中上调。另一方面，电生理实验表明，应用含MIPs细胞的分泌物可在脑巨细胞（CTA的关键中间神经元）和B1运动神经元（颊运动神经元）之间的突触处诱发长时程增强（LTP）。因此，我们推测MIPs和MIP受体在突触处起重要作用，可能是CTA-LTM巩固过程的基础。为了验证这一假设，我们将识别哺乳动物胰岛素受体结合位点且被认为可与MIP受体发生交叉反应的抗体应用于椎实螺的中枢神经系统。我们目前的数据表明，将胰岛素受体抗体应用于离体中枢神经系统可阻断LTP，并且将该抗体注射到椎实螺腹腔中可抑制LTM巩固，但不影响CTA的形成。
