Molecular and cellular analysis of the changes of the expression of steroid hormone receptors and the neuronal function associated with aging.

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We immunohistochemically investigated the GR expression in the brain of aged-rats by means of. In comparison with young adult rats, the reduction of intensity for GR-immunoreactivity was observed in the cerebral cortex, hippocampus and amygdala, which were well associated to the limbic system, in the aged-rats, although the circulating cortiosteroids have been indicated to show an increase with aging.The ultra structural changes on the neurons with aging, especially using a high voltage electron microscopy (HVEM) was also observed. HVEM could reveal the significant reduction of the number of spines in dendrites of CA1 pyramidal neurons and cortical neurons, and the morphological changes of these spines. On the other hand, we immunohistochemically investigated the change of several neurotransmitter relevant enzymes, such as ChAT, GAD, and TH. In the aged rats, the reduction of immunoreactivity for ChAT, as well as GAD were observed in comparison with those in the young rats. On the othe … More r hand, the intensity of TH immunoreactivity did not show any significant changes in aged rats, although the number of TH-immunoreactive cell bodies and fibers seemed to reduce.Moreover, we studied about the expression of annexin-1 in the folliculo-stellate cells in the anterior pituitary under different corticosteroid conditions. After adrenalectomy, LC1 immunoreactivity was almost disappeared, while the immunoreactivity was recovered by corticosterone replacement. The expression of GR immunoreactivity in the nucleus of FS cells also showed a similar pattern to annexin-1 associated with the corticosteroids conditions, however S100 (a marker for FS cells) immunoreactivity was not changed whatever corticosteroids conditions.These results suggest that glucocorticoids regulate the LC1 expression and promote the translocation of annexin-1 from intracellular to pericellular sites in the FS cells of rat anterior pituitary gland to interact with neighboring endocrine cells as a paracrine action. The change of annexin-1 expression in the aged rat is now going to investigate. Less