A new animal model of endogenous depression: a summary of present findings.

In 1982 our laboratory proposed a new animal model of endogenous depression. The proposal was that in rats, neonatally administered clomipramine (CLI) will produce adult animals that model endogenous depression. We summarize here several tests of the validity of the model. Results were that after neonatal CLI, adult male rats showed behavioral abnormalities of the human disorder: decreased sexual, aggressive, and intracranial self-stimulation activities, as well as motor hyperactivity in a stressful situation. Preliminary evidence suggested that behavioral abnormalities in rats (sexual, aggressive, and motor) briefly treated with antidepressant treatments (imipramine, REM sleep deprivation) begin to normalize. Lastly, after neonatal CLI, the adult rats showed REM sleep abnormalities of endogenous depression, viz, low REM latency, frequent sleep onset REM periods, and abnormal temporal course of REM rebound after REM sleep deprivation. These results supported the hypothesis that in rats neonatal CLI produced adult animals that modelled endogenous depression.