Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

Maternal care in the rat influences the development of cognitive function in the offspring through neural systems known to mediate activity-dependent synaptic plasticity. The offspring of mothers that exhibit increased levels of pup licking/grooming (high-LG mothers) show increased hippocampal N-methyl-D-aspartate (NMDA) subunit mRNA expression, enhanced synaptogenesis and improved hippocampal-dependent spatial learning in comparison with animals reared by low-LG mothers. The effects of reduced maternal care on cognitive function are reversed with peripubertal environmental enrichment; however, the neural mechanisms mediating this effect are not known. In these studies we exposed the offspring of high- and low-LG mothers to environmental enrichment from days 22 to 70 of life, and measured the expression of genes encoding for glutamate receptor subunits and synaptophysin expression as a measure of synaptic density. Environmental enrichment reversed the effects of maternal care on synaptic density and this effect was, in turn, associated with a reversal of the effect of maternal care on the NR2A and NR2B subunits of the NMDA receptor, as well as effects on (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits. Finally, direct infusion of an NR2B-specific NMIDA receptor antagonist into the hippocampus eliminated the effects of maternal care on spatial learning/memory in the Morris water maze. These findings suggest that: (1) the effects of maternal care are mediated by changes in NR2B gene expression; and (2) that environmental enrichment reverses the effects of reduced maternal care through the same genomic target, the NR2B gene, and possibly effects on other subunits of the NMIDA and AMPA receptors

Aged rats. --- Ampa receptors. --- Animal. --- Animals. --- Care. --- Cognitive function. --- Density. --- Dentate gyrus. --- Development. --- Enrichment. --- Environmental enrichment. --- Expression. --- Function. --- Gene-expression. --- Gene. --- Genes. --- Glutamate receptors. --- Glutamate. --- Hippocampal. --- Hippocampus. --- Immediate-early gene. --- Learning. --- Level. --- Life. --- Long-term potentiation. --- Maternal care. --- Maternal-care. --- Maternal. --- Mechanisms. --- Memory consolidation. --- Messenger-rna. --- Morris water maze. --- Mother. --- Mothers. --- Neural systems. --- Nmda receptor. --- Plasticity. --- Rat hippocampus. --- Rat. --- Receptor antagonist. --- Receptor. --- Receptors. --- Spatial learning. --- Spatial memory. --- Spatial. --- Synaptic plasticity. --- System. --- Systems. --- Time. --- Water maze.

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

The degree to which memory is enhanced by estrogen replacement in postmenopausal women may depend on environmental factors such as education. The present study utilized an animal model of environmental enrichment to determine whether environmental factors influence the mnemonic and neural response to estrogen. Female mice were raised in standard (SC) or enriched (EC) conditions from weaning until adulthood (7 months). All mice were ovariectornized at 10 weeks, and tested in object recognition and water-escape motivated radial arm maze (WRAM) tasks at 6 months. Each day at the completion of training, mice received injections of 0.1 mg/kg cyclodextrin-encapsulated 17-beta-estradiol (E-2), 0.2 mg/kg E-2, or cyclodextrin vehicle (VEH). At the completion of behavioral testing, hippocampal levels of the presynaptic protein synaptophysin and of brain-derived neurotrophic factor (BDNF) were measured. Enrichment effects were evident in VEH-treated mice; relative to SC-VEH females, EC-VEH females committed fewer working memory errors in the WRAM and exhibited increased hippocampal synaptophysin levels. Estrogen effects depended on environmental conditions. E-2 (0.2 mg/kg) improved object memory only in SC females. The same dose improved working memory in SC females, but somewhat impaired working memory in EC females. Furthermore, both doses reduced hippocampal synaptophysin levels in EC, but not SC, females. In contrast, E-2 reduced hippocampal BDNF levels in SC, but not EC, females. This study is the first to compare the effects of estrogen on memory and hippocampal function in enriched and non-enriched female mice. The results suggest that: (1) estrogen benefits object and working memory more in mice raised in non-enriched environments than in those raised in enriched environments, and (2) the changes induced by estrogen and/or enrichment may be associated with alterations in hippocampal synaptic plasticity. (C) 2004 Published by Elsevier Ltd on behalf of IBRO

Adulthood. --- Aged female mice. --- Animal model. --- Animal-model. --- Animal. --- Bdnf. --- Dendritic spine density. --- Education. --- Enriched environment. --- Enriched. --- Enrichment. --- Environment. --- Environmental enrichment. --- Environments. --- Estradiol. --- Estrogen. --- Factor messenger-rna. --- Female mice. --- Female. --- Females. --- Function. --- Health initiative memory. --- Hippocampal. --- Hippocampus. --- Hormone replacement therapy. --- Injections. --- Level. --- Memory consolidation. --- Memory. --- Mice. --- Model. --- Neurotrophic factor. --- Object recognition. --- Object. --- Plasticity. --- Postmenopausal women. --- Protein. --- Radial arm maze. --- Radial-arm maze. --- Randomized controlled-trial. --- Recognition. --- Replacement. --- Response. --- Spatial reference memory. --- Synaptic plasticity. --- Synaptophysin. --- Task. --- Tasks. --- Time. --- Training. --- Weaning. --- Women. --- Working memory. --- Working-memory.