Related Experiment Videos
Fever alters characteristics of sleep in rats
1Department of Psychology, University of Illinois, Urbana-Champaign 61820.
Abstract:
This study examined the effects of a fungal infection on body temperature (Tb) and sleep states. Tb and sleep were recorded in male rats for 24 hr after a saline injection and 48 hr after a subcutaneous injection of live brewer's yeast, at ambient temperatures (Ta's) of 20 degrees and 30 degrees C. Peak fevers of 1.6-3.1 degrees C occurred within 6-10 hr at both Ta's. The rats remained febrile for the next 12-24 hr. For the first 24 hr postyeast, amounts of SWS increased by 19 +/- 3% at 20 degrees C and 12 +/- 2% at 30 degrees C. Specifically, SWS was significantly increased from hr 5-8 (lights-on) and 13-24 (lights-off) at 20 degrees, and from hr 5-8 and 17-24 at 30 degrees C. Ta did not affect the changes in Tb or the changes in SWS after either saline or yeast. Duration of REMS varied with Ta after saline. After yeast, REMS increased by 21 +/- 12% at 20 degrees and decreased by 28 +/- 6% at 30 degrees C, with the net result that REMS at the two Ta's was equal during the fever. Furthermore, while the rats were febrile the normal diurnal variation in REMS was eliminated. Sleep and Tb returned to control values during the second fever day. These results suggest that an activated immune system both increases SWS and overrides the diurnal and thermoregulatory modulations of REMS.
Insights
Fungal infections increase slow-wave sleep (SWS) and alter rapid eye movement sleep (REMS) duration, overriding normal diurnal and thermoregulatory patterns in rats. Body temperature (Tb) fevers are not affected by ambient temperature.
Area of Science:
- Neuroscience
- Immunology
- Sleep Science
Background:
- Fungal infections can trigger immune responses affecting physiological functions.
- Body temperature (Tb) and sleep patterns are known to be influenced by circadian rhythms and ambient temperature (Ta).
Purpose of the Study:
- To investigate the impact of a fungal infection on body temperature and sleep states in rats.
- To determine how ambient temperature influences these effects.
Main Methods:
- Male rats were injected with live brewer's yeast or saline.
- Body temperature and sleep states (SWS, REMS) were monitored for 48 hours at ambient temperatures of 20°C and 30°C.
Main Results:
- Yeast injection induced fevers (1.6-3.1°C) lasting 12-24 hours, unaffected by ambient temperature.
- Slow-wave sleep (SWS) increased significantly post-infection, with variations based on ambient temperature.
- Rapid eye movement sleep (REMS) duration was altered, and its normal diurnal pattern was eliminated during fever.
Conclusions:
- An activated immune system due to fungal infection increases SWS.
- Immune activation overrides normal diurnal and thermoregulatory influences on REMS.
- Body temperature regulation during fever is independent of ambient temperature in this model.