McGivern Robert F, Zuloaga Damian G, Handa Robert J
Department Psychology, San Diego State University, San Diego, CA 92182, USA.
Physiol Behav. 2009 Oct 19;98(4):416-20. doi: 10.1016/j.physbeh.2009.07.004. Epub 2009 Jul 16.
Studies using restraint to induce psychological stress consistently report the expected hyperthermic response in core body temperature (CBT), but many also report a hypothermic response that precedes the hyperthermia. To understand the conditions that produce hypothermia, and to study sex differences in stress-induced hyperthermia, we measured CBT in male and female rats at 70 and 180 days of age in response to two types of stressors: immobilization through restraint (Plexiglas restrainer) and confinement in a small area (circular wire mesh cylinders that allowed free airflow). Restraint early in the light period induced hypothermia only in 180-day-old males, with no hyperthermia observed during the 30-minute restraint period. Increases in humidity and temperature of the microenvironment due to the larger body weight at this age may contribute to the hypothermia. Hyperthermia during restraint in 70-day-old males was significantly attenuated and delayed in onset compared to the rise in females. All females exhibited a CBT rise of approximately 1.3 degrees C occurring 10-15 min after the onset of restraint. Restraint early in the dark period induced no significant change in CBT in males of either age during immobilization, while females exhibited a small rise of approximately 0.5 degrees C. Confinement early in the light period induced a significant rise of approximately 1.5 degrees C in all groups, with no preceding hypothermia. However, the male response was significantly delayed compared to females. Overall, these results indicate that CBT changes during restraint likely involve both anxiogenic and physiological components, while the marked hyperthermia during confinement is primarily psychological in both sexes.
使用束缚来诱发心理应激的研究一致报告了预期的核心体温（CBT）升高反应，但许多研究也报告了在体温升高之前出现的体温过低反应。为了了解产生体温过低的条件，并研究应激诱导的体温过高的性别差异，我们在70日龄和180日龄的雄性和雌性大鼠中测量了CBT，以应对两种类型的应激源：通过束缚（有机玻璃束缚器）固定和限制在小区域（允许自由气流的圆形金属丝网圆筒）。光照期早期的束缚仅在180日龄雄性大鼠中诱发体温过低，在30分钟的束缚期内未观察到体温过高。由于这个年龄段体重较大，微环境的湿度和温度升高可能导致体温过低。与雌性相比，70日龄雄性大鼠在束缚期间的体温过高明显减弱且发作延迟。所有雌性大鼠在束缚开始后10 - 15分钟出现CBT升高约1.摄氏度。黑暗期早期的束缚在固定期间对两个年龄段的雄性大鼠的CBT均未引起显著变化，而雌性大鼠则出现约0.5摄氏度的小幅升高。光照期早期的限制在所有组中均引起约1.5摄氏度的显著升高，且无先前的体温过低。然而，雄性大鼠的反应比雌性大鼠明显延迟。总体而言，这些结果表明，束缚期间的CBT变化可能涉及焦虑和生理成分，而限制期间明显的体温过高在两性中主要是心理性的。
