Long term continuous environmental enrichment decreases estrogen receptor alpha expression in the female mouse hippocampus.

ROSSETTI MF; MORENO-PIOVANO G; DUDIUK C; VARAYOUD, JORGELINA; MUÑOZ-DE-TORO M; LUQUE EH; RAMOS JG

Congreso; II Reunión Conjunta de Neurociencias.; 2010

It has been shown that estrogens influence neurobiological functions associated with the hippocampus being estrogen receptor alpha (ERa) and beta (ERb) main mediators. In  addition,  some  studies  described  the  beneficial  effects  of  the  exposure  to enriched environments on neuronal plasticity, including structural modifications and cognitive functions. In the present study, we examined the effects of living in a long term continuous enriched environment on the expression of ERa in the female mouse hippocampus.  Enrichment consisted of  social  interaction, stimulation of exploratory behaviour and physical activity. A group of female mice was exposed to an enriched environment, while another group was kept in a standard environment (control group). The animals were kept under the experimental conditions from 2 to 11 months of age. By microsurgery complete hippocampus were extracted, which were individually processed. The expression of ERa mRNA and  transcriptional activity of promoter A, C and F were evaluated by real time RT- PCR. Continuously  enriched  mice  showed  a  significant  decrease  in  the expression  of  ERa  mRNA  when  compared  with  controls  (p  <0.05). However, there was no significant difference (p> 0.05) on the relative activity of each of the ERa gene promoters. These results show that a long term continuous enriched environment produced a down-regulation of the expression of ERa in the hippocampus of female mice. This down-regulation would not be mediated by a differential usage of the promoters studied.