Journal of Applied Physiology, Vol 50, Issue 3 509-512, Copyright © 1981 by American Physiological Society
Chronic chlorpromazine administration in rats: effects on ability to work in the heat
R. Francesconi and M. Mager
To identify and quantitate the effects of chronic chlorpromazine (CPZ)
administration on the ability to work in the heat, 2 mg CPZ were
administered by intraperitoneal injection daily for 14 days to rats
weighing between 250 and 350 g at the time of experimentation. When these
animals exercised in the heat (35 degrees C) to hyperthermic exhaustion
(Tre = 42.5-43 degrees C), it was demonstrated that their endurance
capacity was significantly reduced (P less than 0.001) when compared with
saline-treated controls. Increments in rectal temperature while on the
treadmill were significantly (P less than 0.02) elevated among th
CPZ-treated rats. Exercise on the treadmill to hyperthermic exhaustion
resulted in significantly (P less than 0.001) increased circulating levels
of lactate and potassium when these were compared in blood samples taken
immediately before and after exercise in the heat for both groups, but
creatine phosphokinase levels were unaffected. Additionally, lactate levels
were significantly (P less than 0.05) increased in the postrun blood
samples of CPZ-treated rats when compared with the appropriate
saline-treated controls. We concluded from these studies that chronic
administration of CPZ in rats reduces their ability to work in the heat.
Further, their rate of heat gain while exercising in the heat is increased,
and the combined effects of exercise in the heat and CPZ administration
exacerbated the effects on the clinical chemical indices of heat-exercise
injury.
