Behavioral thermoregulation in mice inoculated with influenza virus.
Mice housed at 30 degrees C and inoculated with a mouse-adapted influenza virus show a fall in body temperature (Tb) and a decrease in food intake to almost 0 grams per day. This study tested whether the fall in Tb could be accounted for by the decreased food intake and whether the fall in Tb was due to a decrease of thermoregulatory set point or to an inability to maintain Tb at set point level. The fall in Tb of influenza-infected mice was greater than that of food-deprived mice. When food deprived, mice given access to a thermal gradient increased their preference for warmer areas in the gradient and, as a result, Tb did not fall as much as Tb of starved mice not given access to a thermal gradient. When infected with influenza virus, mice given a thermal gradient decreased Tb less and at a slower rate than mice not given a gradient. However, this fall in Tb of influenza-infected mice was greater than that of food-deprived mice given a thermal gradient. Mice given a thermal gradient increased their preference for the warmer temperatures after inoculation; this returned to preinoculation preference for cooler temperatures during the later days of infection despite a continuous fall in Tb. Influenza-infected mice given a thermal gradient survived significantly fewer days than infected mice not given a thermal gradient. We conclude that the influenza-induced fall of Tb in mice cannot be explained solely by the decrease in food intake, and is partially due to a decrease in thermoregulatory set point.
Klein
M S
MS
Department of Physiology, University of Michigan Medical School, Ann Arbor 48109.
Conn
C A
CA
Kluger
M J
MJ
D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D004435:Eating / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D009980:Influenza A virus; D008297:Male; D051379:Mice; D009976:Orthomyxoviridae Infections / Q000503:physiopathology*; D013217:Starvation / Q000503:physiopathology