Age-related changes in CREB binding protein immunoreactivity in the cerebral cortex and hippocampus of rats

Although the role of cAMP-response-element-binding protein (CREB) binding protein (CBP) in the neuroprotective mechanisms has been the focus of many studies, very little is known about the expression or function of CBP in aged brains. We have therefore examined age-related changes in CBP expression in the cerebral cortex and hippocampus with an immunohistochemical technique. In the cerebral cortex, the distribution patterns were not different between adult and aged groups, but the staining intensity of CBP was significantly decreased in aged rats. In the hippocampus, a distinct immunoreactivity pattern was observed in the CA1-3 areas and dentate gyrus. CBP immunoreactivity was significantly deceased in the pyramidal layer of CA1-3 regions in aged hippocampus. In the dentate gyrus of aged rats, significant decreases were also found in the granule cell layer and polymorphic layer. The first demonstration of age-related decreases in CBP expression in the cerebral cortex and hippocampus may provide useful data for investigating the pathogenesis of age-related neurodegenerative diseases and depression.