The Monosodium L-glutamate (MSG) syndrome in mice develops independently of housing condition.

The sequelae of neuroendocrine, somatic, and behavioral deficits following neonatal MSG treatment have been well-documented, including obesity and decreased locomotor activity. Recently, it was reported that increased body weight and decreased locomotor activity occurred only in group-housed animals. The studies reported here were designed to systematically explore the effects of housing conditions on MSG-treated mice. All aspects of the MSG syndrome were obtained, regardless of the housing condition. We conclude that housing variables play no role in the production of the MSG syndrome in mice. While all MSG-treatment mice had reduced brain weights (cerebrum) regardless of housing condition, MSG-treated mice raised individually had significantly lighter brains than MSG-treated mice raised in groups.