The Effect of Lesions in the Preoptic/Anterior Hypothalamus on the Reflexive Responses of Rats to Cold Stress.
Abstract
We have been investigating the hypothalamic control of the generation and maintenance of the circadian temperature rhythm (CTR). Using implanted telemetry devices and automatic drinking measures, we monitored the rhythms of body temperature and drinking in rats before and after various types of hypothalamic damage. When we divided the CTR up into five components--phase, amplitude, limits, precision and period--we found that each component could be affected independent of the others. For instance, after lesions of the suprachiasmatic nuclei, the putative 'master clock' in the brain, the phase was altered so that highest body temperature occurred several hours earlier than it did in normals. The amplitude of the CTR was attenuated in most, but not all lesioned rats, and the limits were lower than normal but shorter than 24 hrs, and the precision of the rhythms (when hourly body temperature rose above the daily mean body temperature) was not as regular. In rats with lesions of the medial preoptic area, the phase and period wer normal, but the amplitude of the CTR was greatly exaggerated, as were the limits and the daily mean. In other studies we have shown that the amount of REM sleep is highly dependent on the ambient temperature. After basal forebrain (medial preoptic) lesions, rats that showed no REM sleep at one ambient temperature showed normal amounts at another on the same day.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 15, 1984
- Accession Number
- ADA144020
Entities
People
- E. Satinoff
Organizations
- University of Illinois Urbana–Champaign