Prenatal hypoxia modifies working memory and the activity of hippocampal polyphosphoinositide system in rats

Abstract

The present study was aimed at the analysis of spatial learning abilities in the Morris water maze (working memory) as well as hippocampal levels of phosphatidylinositol 4,5-diphosphates (TPI), phosphatidylinositol 4-phosphates (DPI), phosphotidylinositols (MPI), and expression of the type 1 inositol 1,4,5-trisphosphate receptor (IR3R1) in rats exposed to severe hypobaric hypoxia (ascent to 11 km, 3 h) on prenatal days 14-16 (group 1) or 17-19 (group 2). Exposure to severe hypoxia led to significant elevation of TP 1 and DPI hippocampal levels in juvenile and adult rats in the group 1, however these changes were more pronounced in juvenile rats than in adults. In the group 2, hypoxia up-regulated TPI and DPI hippocampal levels in juvenile rats, but in adult animals of this group just a small TPI level up-regulation was detected. Activation of IR3R1 expression was found to occur in the hippocampus both of juvenile and adult rats in the groups 1 and 2. These finding are consistent with the impaired spatial learning ability we revealed in the Morris water maze, indicative of a working memory deficit in the rat offspring exposed to hypobaric hypoxia during the first half of the last week of pregnancy.