REM sleep abnormalities in a new animal model of endogenous depression

Endogenous depression has reliable REM sleep abnormalities. These include a short REM latency, frequent sleep onset REM periods, and after REM sleep deprivation (RSD), an abnormal temporal course of REM rebound in the presence of a normal total REM rebound. The reliability of these abnormalities suggests that they ought to be present in an animal model of endogenous depression. In 1982, we proposed a new animal model of endogenous depression. Our hypothesis is that in rats neonatal clomipramine (CLI) will produce adult animals that model endogenous depression. In this study we tested the prediction that after neonatal treatment with CLI, adult rats will show the above three REM sleep abnormalities of human endogenous depression. We found that neonatal treatment with CLI produced rats that at age 6 months had shorter REM latency, more sleep onset REM periods than control rats, and after RSD, had an abnormal temporal course of REM rebound in the presence of a normal total REM rebound. The finding of these REM sleep abnormalities supported the validity of the animal model of endogenous depression.