Department of Biology, Houghton College, Houghton, NY 14744, USA; Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Department of Biology, Houghton College, Houghton, NY 14744, USA.
Zoology (Jena). 2020 Apr;139:125751. doi: 10.1016/j.zool.2020.125751. Epub 2020 Jan 24.
Responses to stress are generally mediated through the production of glucocorticoids by the hypothalamic-pituitary-adrenal (or -interrenal) axis. The prolonged production of stress hormones can contribute to delayed wound healing and growth, but little is known about their influence on regeneration following tail autotomy, or exploratory behaviour in autotomized individuals. Here we examined the relationship between stress, regeneration, and exploratory behaviour in Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus) by manipulating corticosterone (CORT) levels via cutaneous patch. First, we measured tail regeneration in salamanders with elevated CORT for 13 weeks after the induction of tail autotomy. Test subjects received a weekly patch to wear for one hour that was saturated with either a low CORT (0.25 mg/ml) or high CORT (0.50 mg/ml) solution. Individuals receiving CORT patches regenerated significantly less of their tail length and volume (versus control), but without exhibiting dose-dependent effects. Second, we used a factorial design to evaluate the effects of autotomy and elevated CORT on exploration within a test arena consisting of low barriers arrayed in concentric rings. Individuals experiencing tail autotomy exhibited significantly less exploratory behaviour indicated by an increased latency to cross first barrier and a decreased number of barriers crossed. Neither elevated CORT (0.50 mg/ml), nor the interaction between elevated CORT and tail autotomy significantly affected salamander activity within the array. Although CORT did not have a direct effect on explorative behaviour, a delay in regeneration attributed to CORT could lead to changes in patterns of movement in autotomized individuals.
对压力的反应通常是通过下丘脑-垂体-肾上腺（或-间肾）轴产生糖皮质激素来介导的。应激激素的长期产生可能导致伤口愈合和生长延迟，但对于它们对尾巴自切后再生的影响，或者对自切个体探索行为的影响知之甚少。在这里，我们通过皮肤贴剂来操纵皮质酮（CORT）水平，研究了阿勒格尼山灰泥蝾螈（Desmognathus ochrophaeus）中的应激、再生和探索行为之间的关系。首先，我们测量了尾巴自切后 13 周内接受高 CORT 处理的蝾螈的尾巴再生情况。测试对象每周接受一次一小时的贴片，贴片上涂有低 CORT（0.25 mg/ml）或高 CORT（0.50 mg/ml）溶液。接受 CORT 贴片的个体尾巴长度和体积的再生明显减少（与对照组相比），但没有表现出剂量依赖性效应。其次，我们使用析因设计来评估尾巴自切和升高 CORT 对由低障碍物排列成同心环的测试场地内探索的影响。经历尾巴自切的个体表现出明显较少的探索行为，表现为首次穿过第一道障碍物的潜伏期增加，穿过的障碍物数量减少。升高的 CORT（0.50 mg/ml），以及升高的 CORT 和尾巴自切之间的相互作用都没有显著影响数组内蝾螈的活动。尽管 CORT 对探索行为没有直接影响，但归因于 CORT 的再生延迟可能导致自切个体的运动模式发生变化。
