. 2012 May 21;33(6):775–782. doi: 10.1038/aps.2012.29

Table 1. Effects of heat exposure (36 °C for 100 min) on survival time in rats treated with vehicle or melatonin immediately after the initiation of heat exposure. Except for the normothermic controls, data are presented as the mean±SD. n=6. ^bP<0.05 compared with Group 1; ^eP<0.05 compared with Group 2.

Treatment group	Survival time (min)
1. Normothermic controls	>480
2. Vehicle-treated heatstroke rats*	59±3^b
3. Melatonin (0.2 mg/kg)-treated heatstroke rats*	65±3
4. Melatonin (1 mg/kg)-treated heatstroke rats*	117±5^e
5. Melatonin (5 mg/kg)-treated heatstroke rats*	186±8^e

Group 1 rats were sacrificed approximately 480 min after the initiation of the experiment (or at the end of the experiment) by an over-dose of anesthetic; otherwise, they should survive more than 480 min.

^*For the groups exposed to 36 °C, the heat stress was withdrawn at 100 min, and the rats were allowed to recover at room temperature (26 °C).