Sloman Katherine A, Montpetit Colin J, Gilmour Kathleen M
Department of Biology, McMaster University, 1280 Main St West, Hamilton, Ont, Canada L8S 4K1.
Gen Comp Endocrinol. 2002 Jun 15;127(2):136-46. doi: 10.1016/s0016-6480(02)00033-3.
The objective of the present study was to investigate the effect of social status on the ability of rainbow trout to secrete the stress hormones, cortisol, and catecholamines. Rainbow trout were confined in pairs for six days to permit the formation of dominance hierarchies. An in situ saline-perfused posterior cardinal vein (PCV) preparation was then used to assess cortisol secretion or release of the catecholamine hormones, adrenaline and noradrenaline, in response to the inclusion of appropriate secretagogues in the perfusate. Fish identified as subordinate on the basis of their behaviour showed a characteristic elevation of circulating plasma cortisol concentrations when compared with dominant fish. When the interrenal cells were stimulated in situ with adrenocorticotropic hormone, subordinate fish displayed a significantly lower rate of cortisol secretion than dominant fish. However, social status had no significant effect on either adrenaline or noradrenaline secretion rates upon stimulation of the chromaffin cells in situ with acetylcholine. These results suggest that the chronic elevation of plasma cortisol associated with subordinate social status in rainbow trout reduces the sensitivity of the cortisol-secreting interrenal cells, presumably through negative feedback mechanisms.
本研究的目的是调查社会地位对虹鳟鱼分泌应激激素、皮质醇和儿茶酚胺能力的影响。将虹鳟鱼成对饲养六天，以形成优势等级制度。然后使用原位生理盐水灌注后腔静脉（PCV）制剂，通过在灌注液中加入适当的促分泌剂，来评估皮质醇的分泌或儿茶酚胺类激素（肾上腺素和去甲肾上腺素）的释放。根据行为确定为从属地位的鱼，与优势鱼相比，其循环血浆皮质醇浓度呈现出特征性升高。当用促肾上腺皮质激素原位刺激肾上腺皮质细胞时，从属鱼的皮质醇分泌速率明显低于优势鱼。然而，在用乙酰胆碱原位刺激嗜铬细胞时，社会地位对肾上腺素或去甲肾上腺素的分泌速率没有显著影响。这些结果表明，虹鳟鱼中与从属社会地位相关的血浆皮质醇长期升高，可能通过负反馈机制降低了分泌皮质醇的肾上腺皮质细胞的敏感性。
