Locomotor activity of the genetically inbred Balb/c mouse strain is suppressed by a socially salient stimulus.

The genetically inbred Balb/c mouse strain shows behavioral hypersensitivity to MK-801 (dizocilpine), a noncompetitive NMDA receptor antagonist. In the current study, the locomotor activity of male Balb/c mice was more severely reduced in the presence of a "stimulus" mouse, compared with the outbred Swiss-Webster mouse strain; reduced locomotor activity of the Balb/c mouse was observed when the stimulus mouse was enclosed and when the two mice were allowed to interact freely. The Balb/c mouse strain with altered endogenous tone of NMDA receptor-mediated neurotransmission may lend itself to the identification of candidate compounds targeting impaired sociability, an important dimension of psychopathology in schizophrenia and autism spectrum disorders (ASDs). Reduced locomotor activity in the presence of a stimulus mouse is a sensitive behavioral outcome measure of impaired sociability.