The distribution and functions of neurons in scleractinian corals remain largely unknown. This study focused on the Arg-Phe amide family of neuropeptides (RFamides), which have been shown to be involved in a variety of biological processes in animals, and performed molecular identification and characterization in the adult scleractinian coral Euphyllia ancora. The deduced amino acid sequence of the identified RFamide preprohormone was predicted to contain 20 potential neuropeptides, including 1 Pro-Gly-Arg-Phe (PGRF) amide and 15 Gln-Gly-Arg-Phe (QGRF) amide peptides. Tissue distribution analysis showed that the level of transcripts in the tentacles was significantly higher than that in other polyp tissues. Immunohistochemical analysis with the FMRFamide antibody showed that RFamide neurons were mainly distributed in the epidermis of the tentacles and mouth with pharynx. Treatment of E. ancora polyps with synthetic QGRFamide peptides induced polyp contraction. The induction of polyp contraction by QGRFamide peptide treatment was also observed in another scleractinian coral, Stylophora pistillata. These results strongly suggested that RFamides play a role in the regulation of polyp contraction in adult scleractinians.

石珊瑚中神经元的分布和功能仍然很大程度上未知。本研究重点关注神经肽 (RFamides) 的 Arg-Phe 酰胺家族，该家族已被证明与动物的多种生物过程有关，并在成年石珊瑚Euphyllia ancora中进行了分子鉴定和表征. 推导的已鉴定 RFamide 前激素原的氨基酸序列预计含有 20 个潜在的神经肽，包括 1 个 Pro-Gly-Arg-Phe (PGRF) 酰胺和 15 个 Gln-Gly-Arg-Phe (QGRF) 酰胺肽。组织分布分析表明，触手中的转录物水平明显高于其他息肉组织。FMRFamide 抗体免疫组化分析显示，RFamide 神经元主要分布在触手的表皮和带有咽部的嘴部。用合成的 QGRFamide 肽处理E. ancora息肉诱导息肉收缩。在另一种石珊瑚Stylophora pistillata中也观察到QGRFamide 肽处理诱导息肉收缩。这些结果强烈表明RFamides在成人巩膜虫的息肉收缩调节中起作用。