Maternal Social Separation of Adolescent Rats Induces Hyperactivity and Anxiolytic Behavior

Exposure to early stressful adverse life events such as maternal and social separation plays an essential role in the development of the nervous system. Adolescent Sprague-Dawley rats that were separated on postnatal day 14 from their dam and litters (maternal social separation, MSS) showed hyperactivity and anxiolytic behavior in the open field test, elevated plus-maze test, and forced-swim test. Biologically, the number of astrocytes was significantly increased in the prefrontal cortex of MSS adolescent rats. The hyperactive and anxiolytic phenotype and biological alteration produced by this MSS protocol may provide a useful animal model for investigating the neurobiology of psychiatric disorders of childhood-onset diseases, such as attention deficient hyperactive disorder.

Microarray Analysis of Gene Expression in Rat Hippocampus of Maternal Social Separation Model

OBJECTIVES: Alteration of hippocampus was demonstrated in the maternal social separation(MSS) pups, separated from dams on postnatal day(pnd) 14 and placed alone. Therefore, to understand the molecular events involved in the MSS, we have initiated a search for gene profiles that are up or down-regulated in the hippocampus of MSS pups. METHODS: Analysis of cDNA microarray was performed by using total RNA extracted from the hippocampus of control and MSS pups on pnd 17. Also, passive-avoidance test was demonstrated on pnd 35. RESULTS: Up-regulation of Nedd4a was observed in the hippocampus of MSS pups. Also, MSS rats showed less elongation of latency in passive avoidance test. CONCLUSION: We suggest that environmental effects of MSS may be altered the neural and/or glial differentiation and synapse formation-related genes which may lead cognitive alterations in MSS rats.