Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Matosinhos, Portugal.
Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal.
PLoS One. 2018 Oct 23;13(10):e0206206. doi: 10.1371/journal.pone.0206206. eCollection 2018.
Unique amongst the teleost, Plotosidae catfish possess a dendritic organ (DO) as a purported salt secreting organ, whereas other marine teleosts rely on their gill ionocytes for active NaCl excretion. To address the role of the DO in ionregulation, ligation experiments were conducted in brackish water (BW) 3‰ and seawater (SW) 34‰ acclimated Plotosus lineatus and compared to sham operated fish. Ligation in SW resulted in an osmoregulatory impairment in blood (elevated ions and hematocrit) and muscle (dehydration). However, SW ligation did not elicit compensatory changes in gill or kidney Na+/K+-ATPase (NKA) activity and/or protein expression while a decrease in anterior intestine and increased in posterior intestine were observed but this was not reflected at the protein level. Following ligation in SW, protein levels of carbonic anhydrase (CA) and V-ATPase B subunit (VHAB) were higher in kidney but either lower (CA) or unchanged (VHAB) in other tissues. Taken together, the osmotic disturbance in ligated SW fish indicates the central role of the DO in salt secretion and the absence of a compensatory response from the gill.
不同于其他硬骨鱼，电鳗科鱼类拥有一个树突状器官（DO），被认为是一个盐分泌器官，而其他海洋硬骨鱼则依赖其鳃离子细胞进行主动的 NaCl 排泄。为了研究 DO 在离子调节中的作用，在半咸水（BW）3‰和海水（SW）34‰中对经过驯化的波纹唇鱼进行结扎实验，并与假手术鱼进行比较。在 SW 中结扎会导致血液（离子和血细胞比容升高）和肌肉（脱水）的渗透压调节受损。然而，SW 结扎并没有引起鳃或肾脏 Na+/K+-ATPase（NKA）活性和/或蛋白表达的代偿性变化，尽管观察到前肠减少和后肠增加，但这并没有在蛋白水平上反映出来。在 SW 结扎后，肾脏中的碳酸酐酶（CA）和 V-ATPase B 亚基（VHAB）的蛋白水平升高，但在其他组织中要么降低（CA）要么不变（VHAB）。总之，结扎 SW 鱼中的渗透压紊乱表明 DO 在盐分泌中的核心作用，以及鳃没有代偿反应。
