The effect of lithium chloride on morphine- and pyrogen-induced hyperthermia in rats

In rats, doses of morphine between 2.5 and 20 mg/kg produced hyperthermia, 50-400 mg/kg lithium chloride induced dose-dependent hypothermia. These doses of lithium chloride inhibited morphine- and pyrogen-induced hyperthermia. The hypothermic effect of lithium may be due to the replacement of sodium ions by lithium ions in the hypothalamus. The antagonism between morphine and lithium is nonspecific.