  It is well known that psychoemotional disorders may be accompanied by
decreased sociability in humans. It has been shown that repeated social defeats
in 10 daily agonistic interactions in male mice led to development of the
expressed level of anxiety and to reduction of communication estimated in the
elevated plus-maze and partition tests, respectively. In the social
interactions test, sociable behavior toward unfamiliar partner and exploratory
activity were dramatically decreased in defeated male mice. Avoidance of
approaching partner was significantly increased. Demonstration of self-grooming
behavior was increased in defeated males. Chronic diazepam treatment (0.5
mg/kg, i.p., 2 weeks) led to significant decrease of anxiety level estimated in
the elevated plus maze test and to improvement of communication in the
partition test. In the social interaction test diazepam completely restored the
level of sociability and exploratory activity and reduced avoidance behavior of
approaching partner. Diazepam did not affect self-grooming demonstration. It is
concluded that main factor which provokes decrease in communication in defeated
male mice is the high level of anxiety. Similarity between changes in social
behavior in defeated mice and symptoms of autism in humans is discussed. It is
supposed that this behavioral approach may be useful for studying the molecular
mechanisms of autistic spectrum disorders, developing under chronic negative
social experiences.

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