Deen CM, Hutchison VH
Department of Zoology, University of Oklahoma, 73019, Norman, OK, USA
J Therm Biol. 2001 Feb 1;26(1):55-63. doi: 10.1016/s0306-4565(00)00026-7.
We examined the effects of acclimation temperature and two doses (2.5 and 25mgkg(-1)) of a pyrogen (lipopolysaccharide, LPS) on behavioral thermoregulation in juvenile green iguanas. Overall means of body temperatures for the three-day trial periods were compared among three groups of animals acclimated at 15, 25, and 34 degrees C. The responses of each group of animals to the two dosages of LPS and a control saline injection were examined. Within each treatment block, animals either chose high body temperatures characteristic of a fever response or chose low body temperatures characteristic of a hypothermic response. Thermoregulation was influenced by interaction effects between and among, and independent effects of, acclimation temperature, dose of LPS, and day. In some treatment blocks, individual lizard mass positively correlated with mean individual body temperature. Mean mass of lizards that chose higher body temperatures within a treatment block was higher than the mean mass of lizards that chose lower body temperatures. From these results, we concluded that LPS may induce two different behavioral thermoregulatory responses: fever or hypothermia. The actual amplitude and direction of body temperature change appears to be affected by acclimation temperature and possibly by mass or energy reserves of the animal. If the energy reserves are not sufficient to sustain the higher rate of metabolism associated with the higher body temperatures of a hyperthermic or feverish state, the animal may resort to hypothermia.
我们研究了驯化温度以及两种剂量（2.5和25毫克/千克）的热原（脂多糖，LPS）对幼年绿鬣蜥行为性体温调节的影响。在分别适应于15、25和34摄氏度的三组动物中，比较了为期三天的试验期内的总体体温均值。检测了每组动物对两种剂量LPS以及对照生理盐水注射的反应。在每个处理组内，动物要么选择具有发热反应特征的高体温，要么选择具有低温反应特征的低体温。体温调节受到驯化温度、LPS剂量和天数之间的交互作用以及独立作用的影响。在一些处理组中，个体蜥蜴的体重与个体平均体温呈正相关。在一个处理组内选择较高体温的蜥蜴的平均体重高于选择较低体温的蜥蜴的平均体重。根据这些结果，我们得出结论，LPS可能诱导两种不同的行为性体温调节反应：发热或低温。体温变化的实际幅度和方向似乎受驯化温度影响，也可能受动物的体重或能量储备影响。如果能量储备不足以维持与高温或发热状态下较高体温相关的较高代谢率，动物可能会采取低温状态。
