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

The aim of the present study was to explore 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 (IP3R1) 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 TPI and DPI hippocampal levels in juvenile and adult rats in group 1, however these changes were more pronounced in juvenile rats than in adults. In group 2, hypoxia upregulated TPI and DPI hippocampal levels in juvenile rats, but in adult animals of this group only a small TPI level upregulation was detected. Activation of IP3R1 expression was found to occur in the hippocampus both of juvenile and adult rats in groups 1 and 2. These data are consistent with our findings on impaired spatial learning ability 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.