Opiate effects on isolation-induced hyperthermia

The effect of brief separation from companions on temperature was studied in 24-day-old chickens. It was found that socially isolated animals became hyperthermic. Alternatively, control animals maintained in groups larger than 6 animals displayed no differences in temperature between the pre- and post-test. Injections of naloxone produced dose-dependent temperature increases in socially housed animals. Finally, while morphine reversed isolation hyperthermia, it had little or no effect on temperature in animals that remained in social groups throughout the experiment. The findings are discussed in terms of endogenous opioid involvement in separation distress and social bonding.