Elucidating the mechanisms of alkaline tolerance in freshwater teleosts will help in the development of commercial saline-alkaline aquaculture. The large-scale loach (Paramisgurnus dabryanus) is a viable species for such aquaculture, but the mechanisms of its tolerance of alkaline water are unclear. Large-scale loach was exposed to 40, 50, and 60 mmol L^-1 NaHCO₃ for 12, 48, and 96 h to evaluate the transcriptional changes of branchial Rhesus (Rh) glycoproteins, and aquaporins (Aqp)1 and Aqp3. Rhag transcript levels increased with longer exposure times. Rhag expression also rose considerably at higher carbonate alkalinities. Rhbg mRNA levels declined significantly under carbonate alkalinity exposure. A marked up-regulation of Rhcg was observed in the gills of the loach. Exposure to 60 mmol L^-1 NaHCO₃ also induced a significant up-regulation of aqp1. By contrast, aqp3 expression was significantly lower after 48 h exposure. The current findings reveal that the large-scale loach up-regulates Rhag and Rhcg to enhance ammonia efflux from the gills when exposed to high alkalinity. It is proposed that this species maintains appropriate osmolality when adapting to an alkaline environment by down-regulating aqp3 (to impede urea removal) and up-regulating aqp1 in the gills (to excrete excessive internal water).

阐明淡水硬骨鱼的耐碱机制将有助于商业盐碱水产养殖的发展。大型泥鳅（鲶鱼) 是此类水产养殖的可行物种，但其耐受碱性水的机制尚不清楚。将大型泥鳅暴露于 40、50 和 60 mmol L ^-1 NaHCO ₃ 12、48 和 96 小时，以评估猕猴鳃 (Rh) 糖蛋白和水通道蛋白 (Aqp)1 和 Aqp3 的转录变化。拉格转录水平随着暴露时间的延长而增加。拉格在较高的碳酸盐碱度下，表达也显着上升。血红蛋白在碳酸盐碱度暴露下，mRNA水平显着下降。明显上调rhcg 在泥鳅的鳃中观察到。暴露于 60 mmol L ^-1  NaHCO ₃ 也诱导显着上调aqp1. 相比之下，aqp3暴露48小时后表达显着降低。目前的研究结果表明，大规模泥鳅上调拉格和rhcg当暴露于高碱度时，以增强氨从鳃中流出。建议该物种在通过下调适应碱性环境时保持适当的渗透压aqp3（阻碍尿素去除）和上调aqp1在鳃中（排出过多的内部水）。