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Biochemical Characterization of α‐Adrenergic Receptors in Human Brain and Changes in Alzheimer‐Type Dementia
Author(s) -
Shimohama Shun,
Taniguchi Takashi,
Fujiwara Motohatsu,
Kameyama Masakuni
Publication year - 1986
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1986.tb00753.x
Subject(s) - yohimbine , prazosin , endocrinology , medicine , alpha 2 adrenergic receptor , receptor , caudate nucleus , adrenergic receptor , chemistry , neuroscience , alpha (finance) , biology , antagonist , construct validity , nursing , patient satisfaction
Using ligand binding techniques, we studied α‐adrenergic receptors in brains obtained at autopsy from seven histologically normal controls and seven patients with histopathologically verified Alzheimer‐type dementia (ATD). Binding of the α‐adrenergic antagonists [ 3 H]prazosin and [ 3 H]yohimbine to membranes of human brains exhibited characteristics compatible with α 1 ‐ and α 2 ‐adrenergic receptors, respectively. Binding of both ligands was saturable and reversible, with dissociation constants of 0.15 n M for [ 3 H]prazosin and 5.5 n M for [ 3 H]yohimbine. [ 3 H]Prazosin binding was highest in the hippocampus and frontal cortex and lowest in the caudate and putamen in the control brains. [ 3 H]Yohimbine binding was highest in the nucleus basalis of Meynert (NbM) and frontal cortex and lowest in the caudate and cerebellar hemisphere in the control brains. Compared with values for the controls, [ 3 H]prazosin binding sites were significantly reduced in number in the hippocampus and cerebellar hemisphere, and [ 3 H]yohimbine binding sites were significantly reduced in number in the NbM in the ATD brains. These results suggest that α 1 and α 2 ‐adrenergic receptors are present in the human brain and that there are significant changes in numbers of both receptors in selected regions in patients with ATD.