Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan, ROC.
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan, ROC.
Fish Shellfish Immunol. 2020 Mar;98:1-9. doi: 10.1016/j.fsi.2019.12.091. Epub 2020 Jan 3.
Tyramine (TA), a biogenic monoamine, plays various important physiological roles including immunological regulation in invertebrates. In this study, the effects of TA on the regulation of immune resistance, carbohydrate metabolism and biogenic monoamine, as well as its signaling pathway in Macrobrachium rosenbergii were determined. Results showed that total haemocyte count, hyaline cells, semigranular cells, and phenoloxidase activity per 50 μL of haemolymph and per granulocyte (the sum of semigranular and granular cells) at 0.5 h as well as phagocytic activity and clearance efficiency to Lactococcus garvieae at 1 h of prawn injected with TA at 1 nmol prawn significantly increased, but the significantly decreased plasma lysozyme activity, phagocytic activity, clearance efficiency, and haemolymph glucose and dopamine were observed in prawn injected with TA at 10 nmol prawn for 0.5 h. Respiratory bursts and haemolymph lactate in two TA-injection treatments at 0.5 h and 0.5-1 h, respectively, were significantly higher than those of the saline control, and in addition, TA depressed dopamine release in a dose-dependent manner after 0.5 h of TA injection. All the examined parameters returned to control levels after prawn injected with TA for 2 h. The inhibited effect of TA (at 10 nmol prawn injection) on the phagocytic activity and clearance efficiency to pathogens was blocked by prazosin (an α1 adrenoceptors antagonist). For prawn received TA for 1 h then challenged with Lactococcus garvieae at 2 × 10 colony-forming units prawn, the survival ratio of TA 1 nmol prawn-injected prawn significantly increased by 20%, compared to the saline-challenged control or TA 10 nmol prawn-injected prawn after 144 h of challenge. These results suggested that the level of dopamine release suppression regulated by TA resulted in the immunoenhancing or immunosuppressive effects in prawn, and the signaling pathways of TA in mediating immune function were through octopamine (OA)/TA receptors.
酪胺（TA）是一种生物单胺，在无脊椎动物的免疫调节中发挥各种重要的生理作用。在这项研究中，确定了 TA 对免疫抵抗、碳水化合物代谢和生物单胺的调节作用，以及其在罗氏沼虾中的信号通路。结果表明，注射 TA 后 0.5 h 时，每 50 μL 血淋巴中的总血细胞计数、透明细胞、半颗粒细胞和酚氧化酶活性以及每颗粒细胞（半颗粒细胞和颗粒细胞之和）的活性，以及注射 TA 后 1 h 时对利斯顿氏球菌的吞噬活性和清除效率显著增加，但注射 TA 后 0.5 h 时，虾血浆溶菌酶活性、吞噬活性、清除效率、血淋巴葡萄糖和多巴胺显著降低，注射 TA 后 10 nmol 虾 0.5 h。在两个 TA 注射处理中，在 0.5 h 和 0.5-1 h 时的呼吸爆发和血淋巴乳酸分别显著高于盐水对照，此外，TA 在注射 TA 后 0.5 h 以剂量依赖性方式抑制多巴胺的释放。注射 TA 2 h 后，所有检查参数均恢复至对照水平。TA（注射 10 nmol 虾）对吞噬活性和清除效率的抑制作用被普萘洛尔（α1 肾上腺素能受体拮抗剂）阻断。对于注射 TA 1 h 然后用 2×10 个集落形成单位的罗氏沼虾挑战的虾，与盐水对照或注射 TA 10 nmol 虾后 144 h 挑战的虾相比，注射 TA 1 nmol 虾的虾的存活率显著增加了 20%。这些结果表明，TA 调节的多巴胺释放抑制水平导致虾产生免疫增强或免疫抑制作用，TA 介导免疫功能的信号通路是通过章鱼胺（OA）/TA 受体。
