Bernier Nicholas J, Alderman Sarah L, Bristow Erin N
Department of Integrative Biology, University of Guelph, 488 Gordon Street, Guelph, Ontario, Canada.
J Endocrinol. 2008 Mar;196(3):637-48. doi: 10.1677/JOE-07-0568.
Corticotropin-releasing factor (CRF)- and urotensin I (UI)-expressing cells of the preoptic area (POA) and caudal neurosecretory system (CNSS) are considered key contributors to the regulation of the stress response in fish; however, the expression pattern of these neurons to environmental and social challenges have not been compared in a single study. Therefore, we characterized in rainbow trout (Oncorhynchus mykiss) the central distribution of CRF and UI expression and quantified the POA and CNSS mRNA levels of both transcripts in response to hyperammonemia, hypoxia, isolation, or subordination. The tissue distribution demonstrated that the POA and the CNSS are dominant sites of CRF and UI expression. Comparison of the plasma cortisol levels in response to the diverse treatments showed that subordination was the most severe stressor followed by hyperammonemia, isolation, and hypoxia. In the POA, with the exception of subordination that had no effect on UI expression, all stressors resulted in increase in CRF and UI mRNA levels. In the CNSS, while hyperammonemia was associated with increase in CRF and UI mRNA levels, and hypoxia induced an increase in CRF expression, isolation caused a decrease in the expression of both transcripts, and subordination had no effect. Independent of the stressor, we found strong positive correlations between CRF and UI expression in the POA and the CNSS, and no correlation in the expression of either gene between regions. Overall, the results demonstrate that the contribution of POA and CNSS CRF and UI neurons to the stress response in rainbow trout is stressor-, time-, and region-specific.
视前区（POA）和尾部神经分泌系统（CNSS）中表达促肾上腺皮质激素释放因子（CRF）和尿紧张素I（UI）的细胞被认为是鱼类应激反应调节的关键因素；然而，尚未在一项研究中对这些神经元对环境和社会挑战的表达模式进行比较。因此，我们对虹鳟（Oncorhynchus mykiss）中CRF和UI表达的中枢分布进行了表征，并量化了POA和CNSS中这两种转录本在高氨血症、缺氧、隔离或从属状态下的mRNA水平。组织分布表明，POA和CNSS是CRF和UI表达的主要部位。对不同处理后血浆皮质醇水平的比较表明，从属状态是最严重的应激源，其次是高氨血症、隔离和缺氧。在POA中，除了从属状态对UI表达没有影响外，所有应激源均导致CRF和UI mRNA水平升高。在CNSS中，高氨血症与CRF和UI mRNA水平升高有关，缺氧诱导CRF表达增加，隔离导致两种转录本的表达减少，而从属状态没有影响。与应激源无关，我们发现POA和CNSS中CRF和UI表达之间存在强正相关，而区域之间任一基因的表达均无相关性。总体而言，结果表明，POA和CNSS的CRF和UI神经元对虹鳟应激反应的贡献具有应激源、时间和区域特异性。
