Journal of Applied Physiology, Vol 64, Issue 3 1076-1078, Copyright © 1988 by American Physiological Society
Mechanism of action of physical antipyresis in the rat
M. Banet
Institute for Normal and Pathological Physiology, Philipps University, Marburg, Federal Republic of Germany.
To study the mechanism of action of physical antipyresis, core temperature
was measured in two groups of rats in which heat loss was increased by cold
exposure and by cooling an inferior cava heat exchanger, respectively, both
before and after infection with Salmonella enteritidis. Cold exposure did
not influence core temperature. On the other hand, cooling the heat
exchanger caused a fall in core temperature of approximately 0.7 degree C,
to 37 degrees C in normothermia and to 38.5 degrees C 24 h after the
infection. These lower core temperatures were then regulated against any
further increase in heat loss until the thermoregulatory metabolic capacity
of the animals was exhausted and a hypothermia developed. It is concluded
that in infectious fever the threshold temperature of shivering increases
as much as core temperature. Furthermore it is suggested that physical
antipyresis, such as sponging with tepid water, induces a moderate but
regulated fall in temperature to about the threshold of shivering and that
its efficacy may increase with ambient temperature.
