In vivo and in vitro effects of high-K+ stress on branchial expression of ROMKa in seawater-acclimated Mozambique tilapia
In vivo and in vitro effects of high-K+ stress on branchial expression of ROMKa in seawater-acclimated Mozambique tilapia
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DOI：
10.1016/j.cbpa.2015.05.017
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发表时间：
2015-09-01
影响因子：
2.3
通讯作者：
Kaneko, Toyoji
中科院分区：
文献类型：
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作者：
Furukawa, Fumiya;Watanabe, Soichi;Kaneko, Toyoji
最近，在鳃离子细胞（ROMKa）中表达的肾外髓K+通道（ROMK）的硬骨鱼直系同源物已成为鱼类的主要K+排泄途径。然而，响应血浆 K+ 水平扰动而调节 ROMKa 表达的机制尚不清楚。在这项研究中，我们的目的是确定广盐鱼的内分泌系统和 K+ 调节之间的潜在联系。我们评估了暴露于高 K+ (H-K) SW 的海水 (SW) 适应的莫桑比克罗非鱼 (Oreochromis mossambicus) 中多种内分泌参数的时程变化，包括血浆皮质醇以及鳃糖皮质激素和盐皮质激素受体（GR1、GR2 和 MR）的基因表达以及垂体激素。暴露于 H-K SW 对血浆皮质醇或 GR 和垂体激素的 mRNA 水平几乎没有影响。由于体内 H-K 处理后 6 小时内血浆 K+ 和鳃 ROMKa 表达增加，因此随后使用不同 K+ 浓度的培养基在鳃丝孵育实验中测试了高 K+ 的效果：在 H-K 培养基中孵育细丝 6 小时后诱导 ROMKa mRNA 水平。本研究首次证明硬骨鱼离子细胞中 ROMKa 的表达可以独立于系统信号传导对高 K+ 条件做出反应。 (C) 2015 Elsevier Inc. 保留所有权利。
Recently, a teleost ortholog of renal outer medullary K+ channel (ROMK) expressed in gill ionocytes (ROMKa) has emerged as a primary K+-excreting pathway in fish. However, the mechanisms by which ROMKa expression is regulated in response to perturbations of plasma K+ levels are unknown. In this study, we aimed to identify potential links between the endocrine system and K+ regulation in a euryhaline fish. We assessed time-course changes in multiple endocrine parameters, including plasma cortisol and gene expression of branchial glucocorticoid and mineralocorticoid receptors (GR1, GR2, and MR) and pituitary hormones, in seawater (SW)-acclimated Mozambique tilapia (Oreochromis mossambicus) exposed to high-K+ (H-K) SW. Exposure to H-K SW elicited little effects on plasma cortisol or mRNA levels of GRs and pituitary hormones. Since plasma K+ and branchial ROMKa expression was increased within 6 h after H-K treatment in vivo, the effect of high K+ was subsequently tested in a gill filament incubation experiment using media with differing K+ concentrations: ROMKa mRNA levels were induced following incubation of filaments in H-K medium for 6 h. The present study is the first to demonstrate that the expression of ROMKa in teleost ionocytes can respond to high K+ conditions independent from systemic signaling. (C) 2015 Elsevier Inc. All rights reserved.