REGIONALLY SPECIFIC AGE-DEPENDENT DECLINE IN ALPHA-2-ADRENOCEPTORS - AN AUTORADIOGRAPHIC STUDY IN HUMAN BRAIN

The effect of sex, postmortem delay and aging on alpha(2)-adrenoceptor binding was studied in tissue sections from several representative regions of the human brain from 21 subjects using [H-3]UK-14304 as a ligand. Sex and postmortem delay did not influence the density of alpha(2)-receptors. Aging resulted in clear decreases in most forebrain areas examined (n. basalis > basal ganglia > hypothalamus > fronto-temporal cortex > hippocampus > visual cortex), whereas alpha(2)-receptors did not significantly change with age in the amygdala and several infratentorial areas. We conclude that age-related, regionally specific decreases in the density of alpha(2)-receptors occur in the human brain. The implications of these findings for age-dependent noradrenergic degeneration are discussed.