Couper J M, Leise E M
Biol Bull. 1996 Oct;191(2):178-186. doi: 10.2307/1542921.
Bath-applied serotonin (5-HT) induces competent larvae of the marine snail Ilyanassa obsoleta to metamorphose. Previously, the mode of action of 5-HT, whether as an external ligand or as an internal neurotransmitter, was unknown. Larvae were injected with 10-4 M 5-HT and other pharmacological agents to provide evidence that serotonergic neurons are necessary for metamorphosis in Ilyanassa larvae and that serotonin functions as a neurotransmitter or neuromodulator during this process. About 50% of 5-HT-injected animals metamorphose within 48 hours. Fluoxetine, a 5-HT reuptake inhibitor, and alpha-methyl-5-hydroxytryptamine (αm5HT), a 5-HT agonist, were also effective inducers of metamorphosis. Gramine (3-[dimethylaminomethyl]indole), a 5-HT antagonist, inhibited the inductive activity of 5-HT, while the amino acid gammaaminobutyric acid (GABA) resulted in rates of morphological restructuring similar to those of controls. Collectively, the results of our experiments support the idea that serotonergic neurons are active during larval metamorphosis of Ilyanassa and that 5-HT does not induce metamorphosis by binding to epidermal chemoreceptors.
浴加血清素（5-羟色胺，5-HT）可诱导海洋蜗牛光帽螺（Ilyanassa obsoleta）的有能力的幼虫变态。此前，5-HT的作用方式，无论是作为外部配体还是作为内部神经递质，都不清楚。给幼虫注射10-4 M 5-HT和其他药剂，以提供证据表明血清素能神经元对光帽螺幼虫的变态是必需的，并且血清素在这个过程中作为神经递质或神经调节剂发挥作用。约50%注射5-HT的动物在48小时内变态。5-羟色胺再摄取抑制剂氟西汀和5-羟色胺激动剂α-甲基-5-羟色胺（αm5HT）也是有效的变态诱导剂。5-羟色胺拮抗剂格拉明（3-[二甲基氨基甲基]吲哚）抑制了5-HT的诱导活性，而氨基酸γ-氨基丁酸（GABA）导致的形态重构速率与对照组相似。总的来说，我们的实验结果支持这样一种观点，即血清素能神经元在光帽螺幼虫变态过程中是活跃的，并且5-HT不是通过与表皮化学感受器结合来诱导变态的。
