Initiation and Inhibition of Shivering in the Rat: Interaction Between Peripheral and Central Factors

Unanaesthetized, female white laboratory rats were subjected to almost square-wave changes in ambient temperature, from 20 degrees C to 35 degrees C, in a small climatic chamber. 2. Intracerebroventricular injections of serotonin and methysergide were made in shivering, unanaesthetized rats. 3. The integrated electromyogram of m. suprascapularis was recorded as a quantitative measure of shivering activity to monitor the effects of the above procedures. 4. Both warm transients and serotonin inhibited shivering, but methysergide blocked only the effect of serotonin.