Tsang Maisie, Fewell James E, Moore Sherry L
Department of Physiology and Biophysics, University of Calgary, Health Sciences Centre, Heritage Medical Research Building, 206, 3330 Hospital Drive, N.W., Calgary, Alberta, Canada T2N 4N1.
Physiol Behav. 2006 Sep 30;89(2):235-40. doi: 10.1016/j.physbeh.2006.06.005. Epub 2006 Jul 17.
Intraperitoneal administration of E. coli LPS in doses that elicit half-maximal (EC50 - 20 ug/kg) and maximal (EC100 - 160 ug/kg) febrile responses in nonpregnant rats produce hypothermia in near-term pregnant rats. The present experiments have been carried out to determine if the hypothermia results from a "regulated" or "forced" thermoregulatory response. Chronically-instrumented pregnant rats were allocated to one of two experimental groups depending upon whether they were studied in an experimental apparatus configured as a metabolic chamber with a uniform ambient temperature of 25 degrees C or configured as a thermocline with a linear temperature gradient ranging from 10 degrees C to 40 degrees C. The pregnant rats developed hypothermia following intraperitoneal administration of 160 ug/kg of E. coli LPS when they were studied in the thermal gradient as well as when they were studied in the uniform thermoneutral environment. They did not attempt to prevent the hypothermia following administration of bacterial pyrogen by moving to a warmer region of the thermocline. Thus, our data provide evidence that the hypothermia which occurs following intraperitoneal administration of an EC100 dose of E. coli LPS results from a regulated rather than a forced thermoregulatory response. The mechanism and consequences of this pregnancy-induced thermoregulatory response to bacterial pyrogen are unknown.
在未怀孕大鼠中能引发半数最大发热反应（EC50 - 20微克/千克）和最大发热反应（EC100 - 160微克/千克）的剂量的大肠杆菌脂多糖经腹腔注射后，会使近期怀孕的大鼠体温过低。进行本实验是为了确定体温过低是由“调节性”还是“强制性”体温调节反应引起的。根据实验装置的配置情况，将长期植入仪器的怀孕大鼠分为两个实验组之一，实验装置要么配置为环境温度均匀为25摄氏度的代谢室，要么配置为温度从10摄氏度到40摄氏度呈线性梯度变化的温梯。当在热梯度环境以及在均匀的热中性环境中对怀孕大鼠进行研究时，经腹腔注射160微克/千克的大肠杆菌脂多糖后，它们都会出现体温过低的情况。它们不会通过移动到温梯中较温暖的区域来试图防止细菌致热原给药后的体温过低。因此，我们的数据提供了证据，表明腹腔注射EC100剂量的大肠杆菌脂多糖后出现的体温过低是由调节性而非强制性体温调节反应引起的。这种怀孕诱导的对细菌致热原的体温调节反应的机制和后果尚不清楚。
