[A method for determination of thermally motivated behavior (author's transl)]

Constant body temperature in homeothermic organisms results from autonomic and behavioral thermoregulatory reactions. The input variables for thermally motivated behavior are temperatures of the skin and of the hypothalamus. Our aim was to determine the behavioral side of thermoregulatory reactions under the influence of drugs interfering with normal body temperature. Initial experiments were made with phentolamine, which at an ambient temperature of + 4 degrees C causes a dose dependent hypothermia. Rats were trained in a cold box to press a lever and were rewarded by a certain amount of warm air. Trained rats were able to raise the temperature in the box from -4 degrees C up to + 4 degrees C at a response rate of 0.5 min. Treated with phentolamine (3.7-15 mg/kg) these rats increased the rate of lever pressing dose dependently, i.e. they increased their ambient temperature. The hypothermic effect of the drug was therby reduced to a certain extent. Using this method it can be determined whether a drug influences body temperature at the level of autonomic reactions or at that of thermally motivated behavior or at those of both.