多巴胺对凡纳滨对虾血细胞免疫作用效应途径的研究

Study on Immunoregulation Mechanism of Hemocytes Mediated by Dopamine in Litopenaeus vannamei

本文通过血细胞体外培养,研究了多巴胺(DA)及多巴胺受体(DARs)拮抗剂对凡纳滨对虾血细胞信号转导通路和免疫防御效应的影响。结果表明:DA及DARs拮抗剂对凡纳滨对虾血细胞内信号通路因子(AC、PLC、cAMP、DAG、PKA、PKC)和免疫防御效应(酚氧化酶原活力、酚氧化酶活力、吞噬率及抗菌活力)影响显著(P <0.05)。在DA作用下血细胞第二信使合成酶(AC、PLC)、第二信使(cAMP、DAG)及蛋白激酶(PKA、PKC)含量显著升高;与DA处理组相比,DARs 1型拮抗剂对血细胞信号通路因子具有显著抑制作用,且表现出剂量效应,而DARs 2型拮抗剂引起AC、cAMP和PKA信号通路因子明显升高,PLC、DAG和PKC信号通路因子无显著变化。DA作用后血细胞酚氧化酶原活力、吞噬率及抗菌活力均显著降低,而胞吐酚氧化酶活力显著升高;与DA处理组相比,DARs 1型拮抗剂对血细胞上述免疫防御效应具有显著抑制作用,且呈剂量效应,而DARs 2型拮抗剂血细胞吞噬活力显著降低,而其他免疫防御效应无显著变化。混合DARs拮抗剂均与1型拮抗剂作用类似。综合上述研究结果得出,DA主要通过凡纳滨对虾膜上1型DAR激活AC-cAMP-PKA和PLC-DAG-PKC信号通路调控血细胞吞噬活力、proPO系统和免疫活性因子的胞吐,2型DARs抑制AC-cAMP-PKA信号通路,辅助调控吞噬作用。

The effects of dopamine (DA)combined with dopamine receptor (DAR)antagonists on im- mune signaling pathway and immune parameters of haemocytes in Litopenaeus vannamei were investigated through in vitro experiments.The results revealed that a significant increase on the second messenger synthetases (AC,PLC),the second messengers (cAMP,DAG)and protein kinases (PKA, PKC)were observed in DA group.The SCH23390(type 1DARs antagonist)could significantly inhibit the effect of DA on the intracellular signaling factors in a dose-dependent manner.Sulpiride (type 2 DARs antagonist)could promote the effect of DA on the intracellular signaling factors markedly (AC, cAMP,PKA).No significant difference in other parameters were observed among the type 2DARs antagonist groups.The results of the study on the haemocytes immune parameters indicated that prophenoloxidase (proPO)activity,phagocytic activity and antibacterial activity in DA group decreased significantly at 3h,while the phenoloxidase (PO)activity increased significantly.Type 1DARs antagonist could significantly inhibit the effect of DA on the immune parameters in a dose-dependent manner.Type 2DARs antagonist could increase the effect of DA on phagocytic activity,while there was no significant changes observed in other immune parameters.All the intracellular signaling factors and immune parameters of the admixture groups shared a similar trend with type 1DARs antagonist groups.In summary,the results suggested that DA could regulate hemocytes phagocytic activity and proPO system through the AC-cAMP-PKA pathway and the PLC-DAG-PKC pathway activated mainly by type 1 DAR.In addition,DA also could regulate hemocytes phagocytic activity through the AC-cAMP-PKA pathway which was inhibited by type 2DAR.