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Region‐Specific loss of α 1 ‐adrenergic receptors in rat brain with aging: A quantitative autoradiographic study
Author(s) -
Burnett Donald M.,
Zahniser Nancy R.
Publication year - 1989
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890040208
Subject(s) - olfactory tubercle , brainstem , aging brain , receptor , endocrinology , cerebellum , medicine , hippocampal formation , thalamus , putamen , cerebral cortex , hippocampus , chemistry , biology , olfactory bulb , neuroscience , central nervous system , disease
The effects of aging on the density and affinity of α 1 ‐adrenergic receptors (α 1 ‐ARs) were studied in several circumscribed areas of the Fischer 344 male rat brain. Computer‐assisted quantitative autoradiography was used to analyze saturation binding isotherms of [ 125 I]BE‐2254, a selective α 1 ‐AR antagonist. Significant decreases in receptor density of 15 and 29% were observed in the thalamus at 16–18 and 24–28 months of age, respectively, when compared to 3–4 month‐old controls. Progressive declines in receptor density of 24 and 44% were also found in the olfactory tubercle. In the cerebral cortex, a significant 26% loss in receptors occured only in the oldest age group. No changes were found in any of the other brain areas investigated, including the cerebellum, brainstem, caudate‐putamen, and several subregional areas of the hippocampal formation. K d values ranged from 12 ± 1.8 pM in the brainstem to 23 ± 1.6 pM in the thalamus and were not affected by aging in any area examined. It is concluded that the density of α 1 ‐ARs in the Fischer 344 rat brain is diminished with aging in a region‐specific manner and that loss of these receptors may account for age‐related functional deficits only in a few brain areas.