Changes Of Expression Of NMDA Receptor In The Young Rat Hippocampus And Learning And Memory Deficits Following Fetal Growth Restriction Induced By Prenatal Passive Smoking

Part I Changes of Ultrastructure and NMDA Receptor NR1 Subunit inThe Neonatal Rat Hippocampus Following Fetal Growth RestrictionInduced by Prenatal Passive smokingObjective: To explore the changes of the ultrastructure of CA1 regions and the expression of NMDA receptor NR1 subunit mRNA in the neonatal rat (postnatal day 1, PND1) hippocampus following fetal growth restriction (FGR) induced by prenatal passive smoking.Methods: Female Sprague-Dawley rats were randomly divided into the model group (MG) and the non-model group (NMG), each group including 12 rats respectively. To set up the model of FGR, the MG was subjected to passive smoking from gestation day 5 to 20. In terms of the FGR standard, the young rats who were FGR in the MG were classified as the FGR group (FG) and the young rats who were non-FGR in the NMG were classified as the control group (CG). The CA1 regions in the neonatal rat hippocampus were prepared for routine electron microscopic section to observe the morphologic details; The expression of NMDA receptor NR1 subunit mRNA was semi-quantitatively determined by reverse transcription-polymerase chain reaction (RT-PCR).Results: (1) The electron microscopic observations in the CA1 regions of FG are as followed: (1) the loss of integrity and dissolution of the cell membrane in neurons; (2) the swelling and disruption and/or loss of cristae in mitochondria; (3) the swelling of rough endoplasmic reticulum; (4) the aggregation of chromatins into different sized discrete masses, attaching around the nuclear membrane. (2) RT-PCR showed that the expression of NR1 subunit mRNA of the FG (0.3811 0.4513) in the neonatal rat hippocampus was significantly lower than that of the CG (0.9318 0.1593,P<0.05).Conclusions: We can observe the changes of the ultrastructure of the CA1 regions and the decreased expression of NMDA receptor NR1 subunit mRNA in the neonatal rats hippocampus following FGR induced by prenatal passive smoking ,which probably is one of the mechanisms to impair the neural functions.