To unveil the neuroendocrine-immune (NEI) mechanism of crustaceans under high ambient ammonia-N, crustacean hyperglycemic hormone (CHH) in L. vannamei was knocked down under 20 mg/L ammonia-N exposure. The results showed that the expression of CHH in the eyestalks decreased significantly when CHH was silenced. After CHH was knocked down, the levels of CHH, ACh, DA, NE, and 5-HT in the haemolymph decreased significantly. Correspondingly, the expressions of GC, ACh₇R, DM1, DA₁R, and 5-HT₇R in haemocytes down-regulated significantly, while DA₄R and α₂AR up-regulated significantly. Besides, the expression of Toll3 reduced significantly. And significantly changes occurred in the levels of G protein effectors (AC and PLC), second messengers (cAMP, cGMP, CaM, and DAG), protein kinases (PKA, PKC and PKG), and nuclear transcription factors (CREB, Dorsal, Relish and NKRF). Furthermore, immune defense proteins (BGBP and PPO3, Crustin A, ALF, LYC, TNFα, and IL-16), phagocytosis-related proteins (Cubilin, Integrin, Peroxinectin, Mas-like protein, and Dynamin-1) and exocytosis-related proteins (SNAP-25, VAMP-2 and Syntaxin) changed significantly. Eventually, a significant decrease in the levels of THC, haemocytes phagocytosis rate, plasma PO, antibacterial and bacteriolytic activities was detected. Therefore, these results indicate that under ammonia-N stress, the combination of CHH and GC mainly affects exocytosis of shrimp through the cGMP-PKG-CREB pathway. Simultaneously, CHH stimulates the release of biogenic amines, and then activate G protein effectors after binding to their specific receptors, to regulate exocytosis mainly via the cAMP-PKA-CREB pathway and influence phagocytosis primarily by the cAMP-PKA-NF-κB pathway. CHH can enhance ACh, and then activate G protein effectors after binding to the receptors, and finally regulate exocytosis mainly through the cAMP-PKA-CREB pathway and regulate phagocytosis by the cAMP-PKA-NF-κB pathway. CHH can also promote Toll3-NF-κB pathway, thereby affecting the expressions of immune defense factors. This study contributes to a further understanding of the NEI mechanism of crustacean in response to environmental stress.

为了揭示高环境氨氮下甲壳类动物的神经内分泌免疫 (NEI) 机制，南美白对虾中的甲壳类动物高血糖激素 (CHH) 在20 mg/L 氨氮暴露下被击倒。结果表明，当CHH沉默时，眼柄中CHH的表达显着降低。后CHH被撞倒，CHH，乙酰胆碱，DA，NE，5-HT的血淋巴水平显著下降。相应地，GC、ACh ₇ R、DM1、DA ₁ R和5-HT ₇ R 的表达在血细胞中显着下调，而DA ₄ R和α ₂ AR显着上调。此外，Toll3的表达显着降低。G蛋白效应子（AC和PLC）、第二信使（cAMP、cGMP、CaM和DAG）、蛋白激酶（PKA、PKC和PKG）和核转录因子（CREB、Dorsal、Relish）的水平发生了显着变化和NKRF）。此外，免疫防御蛋白（BGBP和PPO3、Crustin A、ALF、LYC、TNFα和IL-16）、吞噬作用相关蛋白（Cubilin、Integrin、Peroxinectin、Mas 样蛋白和Dynamin-1）和胞吐作用相关蛋白（SNAP-25、VAMP-2和Syntaxin) 发生了显着变化。最终，检测到 THC 水平、血细胞吞噬率、血浆 PO、抗菌和溶菌活性显着降低。因此，这些结果表明在氨氮胁迫下，CHH和GC的结合主要通过cGMP-PKG-CREB途径影响对虾的胞吐作用。同时，CHH刺激生物胺的释放，然后在与其特异性受体结合后激活G蛋白效应物，主要通过cAMP-PKA-CREB途径调节胞吐作用，主要通过cAMP-PKA-NF-κB途径影响吞噬作用。CHH可增强ACh，与受体结合后激活G蛋白效应子，最终主要通过cAMP-PKA-CREB通路调控胞吐作用，通过cAMP-PKA-NF-κB通路调控吞噬作用。CHH还可以促进Toll3-NF-κB通路，从而影响免疫防御因子的表达。本研究有助于进一步了解甲壳类动物响应环境胁迫的NEI机制。