Reserpine effects on body temperature in maturing mice

1. The effects of a single dose of reserpine (1 mg/kg body wt) have been studied 1 hr and 24 hr after injection. Young mice were tested on days 3, 7, 10 and 14 after birth and compared with 6-week-old adults. 2. Body temperature (Tb) fell in reserpine-treated young animals 1 hr after injection, as compared with vehicle-treated littermate controls; however, the effect was small in 3- and 7-day animals when compared with 10- and 14-days. 3. Tb was significantly depressed in young reserpine-treated animals 24 hr after injection, with greater effects again found in the 10- and 14-day animals. In contrast, the adult animals failed to show an effect on Tb at either 1 hr or 24 hr after injection. 4. A second dose of reserpine 24 hr after the first dose was ineffective in producing further changes in Tb in 3-, 7-, and 10-day animals; but in 14-day and adult animals the second dose produced a significant decrease in Tb.