急性操作胁迫对刀鲚应激反应相关神经内分泌因子的影响

为深入了解刀鲚应激反应中相关神经内分泌因子作用的分子机理,采用手工捕捉的方式对刀鲚进行了急性操作胁迫。通过放射免疫法和化学发光法测定刀鲚应激反应后头肾和血浆皮质醇含量的变化,结果显示,刀鲚胁迫刺激后血浆皮质醇含量极显著性升高,血浆皮质醇浓度平均升高56.48%,头肾皮质醇含量显著性升高,头肾皮质醇浓度平均升高49.68%,表明急性操作胁迫确实引起刀鲚的应激反应。通过同源克隆的方法获得刀鲚促肾上腺皮质激素释放激素(CRH)、硬骨鱼紧张肽(UI)、阿黑皮素原(POMC)基因的部分序列,并应用实时荧光定量PCR(RT-qPCR)方法检测上述神经内分泌因子mRNA的表达变化,结果显示,CRH基因的表达水平极显著性下降,POMC基因的表达水平显著性下降,UI基因的表达水平有下降趋势但不显著。上述结果显示,皮质醇、CRH、UI和POMC等神经内分泌因子通过鱼类下丘脑—脑垂体—肾间腺轴参与刀鲚应激反应的调节,为进一步了解刀鲚胁迫应答的作用机理,实现对其有效调控打下基础。

The effect of acutehandling stress on the stress-related neuroendocrine factor in Coilia nasus

The present study aimed to investigate the changes in mRNA levels for the stress-related neuroendocrine factor in response to the acute handling stress in Coilia nasus.The radioimmunoassay(RIA)and chemical luminal immunoassay(CLIA)were introduced to detect the cortisol levels in plasma and head-kidney.Fish in stress group showed a significant elevation of cortisol concentration in both plasma(P<0.01)and head-kidney(P<0.05).The plasma cortisol concentration and head-kidney cortisol concentration have risen by 56.48% and 49.68%,respectively,suggesting that the acute stress response was instantly induced after handling.Moreover,the partial sequences of C.nasus corticotropin-releasing hormone(CRH),urotensin I(UI)and proopiomelanocortin(POMC)were cloned by homology cloning,and C.nasus brain CRH,POMC and UI mRNA levels were determined by real-time quantitative PCR(RT-qPCR).The CRH(P<0.01)and the POMC(P<0.05)mRNA expressions were significantly suppressed after a half-hour handling stimulation.But there was no significant change in brain UI mRNA level.Taken together,the acute stress response in C.nasus could be regulated by the stress-related neuroendocrine factor,including cortisol,CRH,UI and POMC,via the hypothalamic-pituitary-interrenal stress axis,which gave us a valuable insight into the C.nasus stress system,and could help developing the stress relief strategy for C.nasus.