The control of shivering and non‐shivering thermogenesis in the rat.

Abstract

1. The effect of intraperitoneal administration of propranolol (4, 8 and 12 mg/kg) on colonic temperature was studied in twelve rats during exposure to ambient temperatures of 30, 15 and 5 degrees C. 2. At 30 degrees C, propranolol had no effect on colonic temperature; at 15 and 5 degrees C, however, 4 mg propanolol/kg induced a fall in colonic temperature of about 0‐8 degrees C, whereas 8 and 12 mg propanolol/kg induced a fall of about 1‐5‐2‐0 degrees C. 3. Assuming that the temperature regulations system of the rat has a proportional controller and that the effect of propranolol was due to the blockade of non‐shivering thermogenesis, the results are interpreted as showing that shivering is activated only when heat loss exceeds the capacity for non‐shivering thermogenesis. © 1977 The Physiological Society