Delehanty Brendan, Boonstra Rudy
Department of Biological Sciences, Centre for the Neurobiology of Stress, University of Toronto at Scarborough, Toronto, Ont., Canada M1C 1A4.
Gen Comp Endocrinol. 2009 Jan 15;160(2):176-82. doi: 10.1016/j.ygcen.2008.11.011. Epub 2008 Nov 27.
Researching the physiological ecology of natural populations requires an understanding of the impact of capture-induced stress because of its numerous effects on physiological processes. In many cases, initial blood samples to which comparisons are made are obtained well after capture and may differ markedly from free-ranging conditions. We examined the extent to which stress profiles of male Richardson's ground squirrels (Spermophilus richardsonii) were affected by short-term responses to live trapping. We compared stress profiles of true base animals (blood samples obtained <3 min of capture) with those of nominal base animals (blood samples obtained >1 h after capture). Total cortisol increased almost 40% whereas our measure of corticosteroid binding globulin (CBG) decreased by 21%, resulting in a two-fold increase in free cortisol levels in nominal base animals compared with true base animals. Capture caused androgen concentrations to fall to almost half of those of true base animals. Energy mobilization increased markedly (22% in glucose and 221% in free fatty acids). Although white blood cell counts did not change, the number of neutrophils was 48% higher in true base animals. There were no changes in hematocrit or lymphocyte counts. Although most of the changes were predictable, the changes in CBG and androgens were unexpected based on previous work on closely related Arctic ground squirrels (Spermophilus parryii). Our results emphasize the value of obtaining true base measurements whenever possible in order to assess the directions and degree of bias introduced by trapping.
研究自然种群的生理生态学需要了解捕获诱导应激的影响，因为它对生理过程有诸多影响。在许多情况下，用于比较的初始血液样本是在捕获后很长时间才获得的，可能与自由放养条件下有显著差异。我们研究了雄性理查森地松鼠（Spermophilus richardsonii）的应激状况受活捉短期反应的影响程度。我们将真正的基础动物（捕获后<3分钟采集的血液样本）与名义基础动物（捕获后>1小时采集的血液样本）的应激状况进行了比较。总皮质醇增加了近40%，而我们测量的皮质类固醇结合球蛋白（CBG）下降了21%，导致名义基础动物的游离皮质醇水平相比真正的基础动物增加了两倍。捕获导致雄激素浓度降至真正基础动物的近一半。能量动员显著增加（葡萄糖增加22%，游离脂肪酸增加221%）。虽然白细胞计数没有变化，但真正的基础动物中性粒细胞数量高出48%。血细胞比容或淋巴细胞计数没有变化。尽管大多数变化是可预测的，但基于之前对密切相关的北极地松鼠（Spermophilus parryii）的研究，CBG和雄激素的变化是出乎意料的。我们的结果强调了尽可能获取真正基础测量值的价值，以便评估捕获引入的偏差方向和程度。
