Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan.
J Neuroendocrinol. 2012 May;24(5):818-30. doi: 10.1111/j.1365-2826.2012.02282.x.
The mRNA expression of genes for corticotrophin-releasing hormone (CRH) and the hormone receptors CRH-receptor/CRH-R, glucocorticoid receptor 1/2 (GR1/2) and mineralocorticoid receptor (MR) was studied in the brain, pituitary and gill of tilapia (Oreochromis mossambibus) during salinity and handling stress by real-time quantitative-polymerase chain reaction analysis. The results indicated that the transcripts of CRH and CRH-R were increased in the forebrain, midbrain and gill, whereas elevated hypothalamic CRH mRNA suppressed the CRH-R mRNA in the pituitary in seawater (SW) fish. The levels of plasma osmolality and cortisol were significantly increased in SW compared to freshwater fish. The up-regulation of GR1, GR2, MR and α-NKA (Na(+) /K(+) -ATPase) transcripts in SW fish provided evidence that cortisol responds to stress and involves ion-base regulation via the GR1, GR2 and MR receptors in the gill. These data suggest that GR1, GR2 and MR have a pivotal role in the brain and gill. GR1, GR2 and MR expression may be dependent on CRH and cortisol expression in the brain and gill. In addition, we performed in situ hybridisation analysis to localise and differentiate the CRH, CRH-R, GR1, GR2 and MR transcripts in the brain of FW- and SW-acute acclimated tilapia during salinity stress. In almost all transcripts, the hybridisation signal was significantly abundant in the SW-acute acclimated tilapia brain, especially in the dorsal ventral cephalon, dorsal nucleus preopticus pars magnocellularis and dorsal nucleus preopticus pars parvocellularis. Salinity stress induced differential and specific responses in the gill and brain compared to handling stress.
采用实时定量聚合酶链反应分析方法，研究了罗非鱼（Oreochromis mossambicus）在盐度和应激处理过程中，大脑、垂体和鳃中促肾上腺皮质激素释放激素（CRH）及其激素受体 CRH 受体/CRH-R、糖皮质激素受体 1/2（GR1/2）和盐皮质激素受体（MR）的基因 mRNA 表达。结果表明，CRH 和 CRH-R 的转录本在前脑、中脑和鳃中增加，而海水（SW）鱼下丘脑中 CRH mRNA 的升高抑制了垂体中的 CRH-R mRNA。与淡水鱼相比，SW 鱼的血浆渗透压和皮质醇水平显著升高。SW 鱼 GR1、GR2、MR 和α-NKA（Na(+) / K(+) -ATPase）转录本的上调表明，皮质醇对应激反应作出响应，并通过 GR1、GR2 和 MR 受体参与离子基础调节。这些数据表明，GR1、GR2 和 MR 在大脑和鳃中具有关键作用。GR1、GR2 和 MR 的表达可能依赖于大脑和鳃中 CRH 和皮质醇的表达。此外，我们还进行了原位杂交分析，以定位和区分 FW 和 SW 急性驯化罗非鱼在盐度应激期间大脑中 CRH、CRH-R、GR1、GR2 和 MR 转录本。在几乎所有的转录本中，SW 急性驯化罗非鱼大脑中的杂交信号明显丰富，尤其是在背腹颅、大细胞视前核背侧部和小细胞视前核背侧部。与应激处理相比，盐度应激在鳃和大脑中引起了不同的、特定的反应。
