ИСТИНА

Blockade of histone deacetylase was shown to improve learning in adult animals (Levenson et al., 2004). The 129sv neonates demonstrate ineffective odor learning with imitation of mother’s licking. This is correlated with low level of maternal care by 129sv females (Aleksandrova et al., 2005). In the present study we were interested, whether the blockade of histone deacetylase by sodium valproate (50 mg/kg s.c., single on day 3 or multiple on days 3-6) will affect the early olfactory discrimination learning of 129sv pups and later maternal behavior of the same female mice in the adulthood. Control groups received saline according to the same regimens. Intact group did not receive injections. At the same time the maternal behavior of dams was examined. At Day 8, pups were trained by stroking in the presence of mint odor and tested 24 hours later. No significant differences in learning were found between experimental and intact male groups, probably due to the fact that in the development the level of acetylation in male brain is higher than in female (Tsai et al., 2009). In females, the most efficient learning was observed following multiple saline injections, while the least efficient learning appeared following single sodium valproate injection compared with intact group. This could be associated with the fact that after stressful procedure of saline injection pups received significantly more grooming from their mothers (Johnston & Walker, 2003). According to our previous data increased maternal care improves early learning in pups. Level of early learning in the female offspring correlated with the level of maternal care of their mothers and with their own level of maternal behavior in the adulthood. Thus, the histone deacetylase inhibitor sodium valproate did not lead to expected improvement in early learning of 129sv neonates, and in improvement of maternal behavior in the adulthood.