Enriched environment, brain nitric oxide synthase and synaptic plasticity in pre-pubertal and young rats.

LORES ARNAIZ, S.; BUSTAMANTE, J.; CZERNICYNIEC, A.; GONZÁLEZ GERVASONI, M.; RODIL MARTÍNEZ, A.; PAGLIA, N.; BOVERIS, A.; LORES ARNAIZ, M.R.

Buenos Aires, Argentina

Congreso; XII Biennial Meeting of the Society for Free Radical Research.; 2004

Society for Free Radical Research

Male Sprague-Dawley rats were randomly assigned to enriched or standard environment at weanling or at 73 days of age, for 17 days. Half of the rats of each rearing condition were handled (8 days) and trained (8 days) in shaping in an 8-arms radial maze with 8 external cues. At 38 days (pre-pubertal) or at 90 days of age (young), rats were sacrificed and brain neuronal and mitochondrial nitric oxide synthase (nNOS and mtNOS) activities were assayed. Western blot analysis of brain mtNOS was conducted. In the pre-pubertal group, enriched rats significantly increased the ratio number of correct arms/total arms and showed habituation from day 1-8 of shaping, while standard rats showed a random performance and no habituation. The activity of nNOS and mtNOS were 80% and 40% increased in enriched rats respectively as compared with standard rats. Western blot analysis showed a higher expression of brain mtNOS in enriched rats than in standard rats. Handling and training also increased nNOS and mtNOS activities by 82% and 68% in standard reared, but not in enriched rats. In the young group, both enriched and standard rats showed a random performance from day 1-8 of shaping, and no significant differences in enzyme activities were found. These results sustain the hypothesis that age, environment and training modulate neuronal plasticity through NO-dependent mechanisms.