Related Experiment Videos
Endotoxin fever in the rat
Acta Physiologica Academiae Scientiarum Hungaricae
|January 1, 1979
Summary
E. coli endotoxin causes a biphasic fever response in rats, involving heat production and loss mechanisms. Environmental and initial body temperature influence the response pattern and dominant effectors.
Area of Science:
- Physiology
- Thermoregulation
- Immunology
Background:
- Fever is a complex physiological response to infection or inflammation.
- Endotoxins from bacteria like E. coli are potent pyrogens that trigger fever.
- The interplay between environmental temperature and host physiology in fever is not fully understood.
Purpose of the Study:
- To investigate the biphasic febrile response to E. coli endotoxin in rats.
- To determine the influence of ambient temperature and initial body temperature on the febrile response patterns.
- To elucidate the coordinated roles of heat production and heat loss mechanisms during endotoxemia.
Main Methods:
- Intravenous administration of E. coli endotoxin to rats.
- Monitoring body temperature at thermoneutral, warmer, and cooler (20°C) ambient temperatures.
- Assessing heat production (brown fat thermogenesis) and heat loss (tail vasomotor changes) effectors.
Main Results:
- A biphasic febrile response (temperature rise-fall-rise) was observed at thermoneutral/warmer temperatures.
- At 20°C, the biphasic pattern was present, but a dominant temperature fall occurred.
- Both heat production (interscapular, periaortic brown fat) and heat loss mechanisms were involved.
- Initial body temperature significantly influenced the effector functions engaged.
Conclusions:
- The febrile response to endotoxin is biphasic and temperature-dependent.
- Ambient and initial body temperatures modulate the balance between heat production and loss.
- Coordinated thermoregulatory mechanisms are crucial in adapting to endotoxemia under varying environmental conditions.