Effects of Glucocorticoids on Age-Related Impairments of Hippocampal Structure and Function in Mice

Abstract

Effects of glucocorticoids (GCs) on maze-learning performances and hippocampal morphology were observed in male C57BL/6Cr mice. Correlations between aging, GCs and maze-learning performances were also studied. (2) Eight-arm radial maze was used in maze-learning tests. Learning performance was assessed by the parameters of time of getting all the bait, number of reentry errors into the already-entered arm with bait, and number of missed entries into an unbaited arm. Brain sections, 8 mum thick, were Nissl-stained with cresyl violet or stained immunocytochemically with antibodies against neurofilaments. (3) With aging, normal pyramidal cells decreased gradually in amount, and degenerating cells increased since the age of 18 months, accompanied with the maze-learning deficit. Here we have suggested that these changes were associated with the age-related deficits in adaptation tolerance of neurons to stress. In addition, the age-related deficits in plasticity of hippocampal neurons to GCs in young mice (3 months of age) resulted in an increase in plasma corticosterone (CORT) concentrations, degeneration of hippocampal pyramidal cells, as well as maze-learning deficits. (4) In conclusion, our data indicated that CORT caused the degeneration of hippocampal pyramidal cells and the impairment of memory.

Time Course of Postnatal Distribution of Doublecortin Immunoreactive Developing/Maturing Neurons in the Somatosensory Cortex and Hippocampal CA1 Region of C57BL/6 Mice

“…It is well known that the cerebral cortex plays an important role in cognition, sensory perception, and motor coordination (Igaz et al 2006;He et al 2008;Hisaoka et al 2010). The hippocampus, a part of limbic system in the brain, is involved in memory formation and affective state.…”

Calbindin D-28k Immunoreactivity and Its Protein Level in Hippocampal Subregions During Normal Aging in Gerbils

“…Changes and abnormalities in aging are related to neuropathological and neurochemical alterations in the central nervous system (Ferrini et al 2002;He et al 2008). These changes include deficits of cognitive processes, especially learning and memory (Armstrong et al 2003;Bevilaqua et al 2008).…”

Ribosomal Protein S3 Immunoreactivity in the Young, Adult and Aged Gerbil Hippocampus

“…Aging is related to neuropathological, neurochemical, structural and functional alterations in the central nervous system [8,17]. These alterations have been associated with accumulation of DNA damage, generation of various oxidants and decrease of antioxidant enzymes during aging [1,22,23].…”