ENVIRONMENTAL ENRICHMENT MODULATES BEHAVIOR AND MESOCORTICOLIMBIC DOPAMINE SYSTEM IN YOUNG ADULT RAT
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Rats raised in an environmental enrichment during development have shown various neurological effects. The present study was carried out to determine whether environmental enrichment can modulate behavioral performances, dopamine (DA) metabolism, and gene expression in mesocorticolimbic dopaminergic (DAergic) system. Beam walk ability test and cylinder test were used for behavioral assessments, HPLC was used for DA metabolism in nucleus accumbens (NAC) and DNA microarray was used for analysis of gene expression in medial prefrontal cortex (mPFC). Rats raised in an enriched environment (enriched rats) showed a good performance on beam walking from the first trial, while rats raised in a standard environment (standard rats) showed a, poor performance but improve gradually by daily successive trials. Enriched rat showed less rearing and more inactivity in the cylinder, while standard rats showed frequent rearing and less inactivity. Microarray analysis in m PFC revealed the increase in gene expression of dopa decarboxylase, the enzyme catalyzes the production of DA. Furthermore, microdialysis in the NAC indicated that enriched rats showed a lower level in 3, 4-dihydroxyphenylacetic acid and homovanillic acid, major metabolites of DA. The effect of methamphetamine on DA turnover were on a same way between the groups. Data suggest that environmental enrichment alters the motivational behavior and modulates mesocorticolimbic DAergic system.
- Nagoya medical journal
Nagoya medical journal 48(2), 139-151, 2007-02-28
Nagoya City University