GMPc, Groupe Mémoire et Plasticité Comportementale, EA 4259, University of Caen Basse-Normandie, 14032 Caen Cedex, France.
Neurobiol Learn Mem. 2010 Feb;93(2):240-7. doi: 10.1016/j.nlm.2009.10.004. Epub 2009 Oct 24.
The vasopressin (VP)/oxytocin (OT)-related peptides constitute a large superfamily found in a wide range of both vertebrate and invertebrate species. While intensive literature reports that these neuropeptides influence behavior, especially learning and memory, in numerous species from diverse vertebrate groups, their roles in behavioral regulation have never been studied in invertebrates. Here, we investigated the role of two VP/OT superfamily peptides, octopressin (OP) and cephalotocin (CT), on long-term memory (LTM) formation of a passive avoidance task in a cephalopod mollusc, the cuttlefish, Sepia officinalis. Subadult cuttlefish were intravenously injected, in a dose range of 3-60 microg/kg, 1h after the training phase (consolidation design); retention performance was tested 24h post-training. We found that administration of OP at low dose (3 microg/kg) enhanced LTM, whereas a dose of 60 microg/kg attenuated it. No effect of OP on LTM was observed for the 15 microg/kg dose. Conversely, an enhancement of retention performance was observed at all doses of CT tested. This study is the first to demonstrate the behavioral effects of VP/OT superfamily peptides in an invertebrate species. The valuable role of VP/OT-like peptides on memory processes offers new evolutionary perspectives on peptidergic transmission and neuromodulation.
血管加压素（VP）/催产素（OT）相关肽构成了一个广泛存在于脊椎动物和无脊椎动物中的大家族。虽然有大量文献报道这些神经肽会影响行为，尤其是学习和记忆，在来自不同脊椎动物群体的众多物种中，但它们在无脊椎动物行为调节中的作用从未被研究过。在这里，我们研究了两种 VP/OT 超家族肽，章鱼加压素（OP）和脑啡肽（CT），在头足类软体动物乌贼（Sepia officinalis）的被动回避任务的长期记忆（LTM）形成中的作用。亚成体乌贼在训练阶段（巩固设计）后 1 小时内以 3-60μg/kg 的剂量范围静脉注射；在训练后 24 小时进行保留性能测试。我们发现，低剂量（3μg/kg）的 OP 增强了 LTM，而 60μg/kg 的剂量则减弱了它。OP 在 15μg/kg 剂量下对 LTM 没有影响。相反，在测试的所有 CT 剂量下都观察到保留性能的提高。这项研究是首次在无脊椎动物物种中证明 VP/OT 超家族肽的行为效应。VP/OT 样肽在记忆过程中的重要作用为肽能传递和神经调节提供了新的进化视角。
