The exploration of a new environment leads to the modulation of gene expression for prolonged times in the rat.

In the present study we performed a transcriptional analysis in order to evaluate changes in gene expression induced by exploration in prolonged times. The analysis was carried out 3, 10 and 20 days after exploration. We analyzed the modulation of the expression levels of Pfn2, Casp3, Pdrg1, Pea15, Ywhaz genes which previously were found not modulated 2 days after exploration. Our data show that the expression of Pfn2, Casp3, Pdrg1, Pea15, Ywhaz genes was modulated at 10 or 20 days. The transcript, whose expression had been evaluated with the qRT-PCR, code for proteins which belong to the following functional categories: synaptic modulation, apoptosis, signal transduction. It is interesting to note that the modulation of the expression of these genes was evident some days after environmental exploration, and not previously at 2 days after conditioning as occurred after contextual fear conditioning (CFC). Hence it is possible to hypothesize that the spatial memory processes require a longer period of elaboration than the emotional ones, fundamental for the survival of the species.