Effect of alcohol on behavioral and autonomic thermoregulation in mice.

Male, BALB/c mice were injected intraperitoneally with ethyl alcohol (ethanol) in dosages of 0, 0.03, 0.1, 0.3, 1.0, or 3.0 g/kg and then placed in a temperature gradient which permitted the measurement of preferred ambient temperature (Ta). The 3 g/kg dosage of ethanol resulted in a slight, but statistically equivocal, lowering of the preferred Ta during the first 30 min of placement in the gradient. A replication of this experiment using a higher sample size indicated that a 3 g/kg dosage of alcohol caused a statistically significant decrease in preferred Ta. In another experiment, BALB/c mice were treated with the aforementioned ethanol dosages while metabolic rate (MR), evaporative water loss (EWL), and colonic temperature were measured 60 min postinjection at Ta's of 20, 30, and 35 degrees C. At a Ta of 20 degrees C a dosage of 3 g/kg caused a significant decrease in MR, EWL, and colonic temperature. At a Ta of 30 degrees C this same dosage caused significant reduction in colonic temperature, however; at a Ta of 35 degrees C ethanol had no effect on these parameters. In conclusion, mice treated with a relatively large dose of ethanol will select a significantly cooler Ta, which is associated with hypothermia. These combined behavioral and autonomic thermoregulatory effects suggest that ethanol led to a decrease in the set-point body temperature.