Early social isolation disrupts latent inhibition and increases dopamine D2 receptor expression in the medial prefrontal cortex and nucleus accumbens of adult rats

Adolescence is a critical period for neurodevelopment. In the present study, we investigated the effects of peri-adolescent social isolation on latent inhibition (LI) and dopamine D2 receptor expression in the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc) of young adult rats. Male Sprague–Dawley rats were randomly divided into adolescent isolation (ISO; isolated housing, 21–34 days of age) and social housing (SOC) groups. LI was tested at postnatal day 56. After behavioral testing, the number of dopamine D2 receptor-expressing cells was determined using immunohistochemistry. Adolescent social isolation impaired LI and increased the number of cells expressing the D2 receptor in the mPFC and NAc. The results suggest that adolescent social isolation produces profound effects on cognitive and dopaminergic function in adult rats, and could be used as an animal model of various neurodevelopmental disorders.

► This study shows that adolescent social isolation impair LI in young adult rats. ► This study shows that isolation increases D2 receptor expression in the mPFC and NAc. ► This study advances the use of isolation rearing as an animal model of mental disease.