NON-ADRENOCEPTOR [H-3] IDAZOXAN BINDING-SITES (I2-IMIDAZOLINE SITES) ARE INCREASED IN POSTMORTEM BRAIN FROM PATIENTS WITH ALZHEIMERS-DISEASE

The 12-imidazoline site (a non-adrenergic mitochondrial site for which a glial location has been proposed and that is associated with the B- form of the enzyme monoamine oxidase) was evaluated in Postmortem cort ical membranes from 9 subjects with Alzheimer's disease (AD) and 9 mat ched-controls by using [H-3]idazoxan (0.6-30 nM) in the presence of 10 (-6) M (-)-adrenaline to prevent binding to alpha2-adrenoceptors. In A D the density (B(max)) of I2-imidazoline sites was significantly highe r (+63%) than in controls whereas no differences were apparent in affi nity values (K(d)). The results support the hypothesis that the I2 imi dazoline site has a major location on glial (astrocyte) cells.