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.