C-type allatostatins (C-type ASTs) are a family of structurally related neuropeptides found in a wide range of insects and crustaceans. To date, the C-type allatostatin receptor in crustaceans has not been deorphaned, and little is known about its physiological functions. In this study, we aimed to functionally define a C-type ASTs receptor in the mud crab, Scylla paramamosian. We showed that C-type ASTs receptor can be activated by ScypaAST-C peptide in a dose-independent manner and by ScypaAST-CCC peptide in a dose-dependent manner with an IC₅₀ value of 6.683 nM. Subsequently, in vivo and in vitro experiments were performed to investigate the potential roles of ScypaAST-C and ScypaAST-CCC peptides in the regulation of ecdysone (20E) and methyl farnesoate (MF) biosynthesis. The results indicated that ScypaAST-C inhibited biosynthesis of 20E in the Y-organ, whereas ScypaAST-CCC had no effect on the production of 20E. In addition, qRT-PCR showed that both ScypaAST-C and ScypaAST-CCC significantly decreased the level of expression of the MF biosynthetic enzyme gene in the mandibular organ, suggesting that the two neuropeptides have a negative effect on the MF biosynthesis in mandibular organs. In conclusion, this study provided new insight into the physiological roles of AST-C in inhibiting ecdysone biosynthesis. Furthermore, it was revealed that AST-C family peptides might inhibit MF biosynthesis in crustaceans.

C 型 allatostatins (C 型 ASTs) 是在广泛的昆虫和甲壳类动物中发现的结构相关的神经肽家族。迄今为止，甲壳类动物中的 C 型 allatostatin 受体尚未脱孤，对其生理功能知之甚少。在这项研究中，我们的目的是在功能上定义泥蟹中的 C 型 AST 受体，青蟹. 我们发现 C 型 ASTs 受体可以被激活西帕AST-C 肽以剂量独立的方式通过 西帕AST-CCC 肽呈剂量依赖性，IC ₅₀值为 6.683 nM。随后，体内 和 体外 进行了实验以研究其潜在作用 西帕AST-C 和 西帕AST-CCC 肽在调节蜕皮激素 (20E) 和法尼酸甲酯 (MF) 生物合成中的作用。结果表明西帕AST-C 抑制 Y 器官中 20E 的生物合成，而 西帕AST-CCC 对 20E 的生产没有影响。此外，qRT-PCR 显示西帕AST-C 和 西帕AST-CCC显着降低了下颌器官MF生物合成酶基因的表达水平，表明这两种神经肽对下颌器官MF生物合成有负面影响。总之，这项研究为 AST-C 在抑制蜕皮激素生物合成中的生理作用提供了新的见解。此外，研究表明 AST-C 家族肽可能会抑制甲壳类动物的 MF 生物合成。