Briese E
Universidad de Los Andes, Mérida, Venezuela.
Brain Res Bull. 1989 Jul-Aug;23(1-2):137-44. doi: 10.1016/0361-9230(89)90172-x.
Rats with lesions in the medial preoptic area were placed in a thermocline where they could choose ambient temperatures (Ta) ranging from 17 to 31 degrees C. The hypothalamic temperature (Thy) and the selected Ta were continuously recorded. Amplitude of Thy circadian oscillations was exaggerated in 23 out of 27 lesioned animals. Only in 6 circadian cycles out of the 158 recorded, the rats chose a higher Ta during the night. In 55% of the recordings the preferred Ta was significantly lower during the night than during the day and out of phase with Thy. In the other 36% of the recorded cycles no significant difference was found between the night and day preferred Ta. Therefore in 91% of the recorded cycles the preferred Ta oscillations did not support the idea that the exaggerated circadian oscillations of Thy in lesioned rats would be due to exaggerated cyclical shifts of the set-point temperature. The lesions induced many sporadic anomalies in the behavior of the rats in choosing a preferred Ta. Short episodes of almost parallel variations in Thy and Ta in phase with each other suggest that some lesions induce an instability of the set-point mechanism.
在内侧视前区有损伤的大鼠被放置在一个温度梯度装置中，在那里它们可以选择17至31摄氏度的环境温度（Ta）。下丘脑温度（Thy）和所选的Ta被连续记录。27只损伤动物中有23只的Thy昼夜振荡幅度增大。在记录的158个昼夜周期中，只有6个周期大鼠在夜间选择了较高的Ta。在55%的记录中，夜间偏好的Ta明显低于白天，且与Thy不同相位。在另外36%的记录周期中，昼夜偏好的Ta没有显著差异。因此，在91%的记录周期中，偏好的Ta振荡并不支持损伤大鼠中Thy昼夜振荡增强是由于设定点温度的周期性变化增强这一观点。损伤在大鼠选择偏好Ta的行为中诱发了许多零星的异常情况。Thy和Ta几乎平行变化的短时间同步发作表明，一些损伤会导致设定点机制的不稳定。
