Non-adrenoceptor [3H]idazoxan binding sites (I2-imidazoline sites) are increased in postmortem brain from patients with Alzheimer's disease.
The I2-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 cortical membranes from 9 subjects with Alzheimer's disease (AD) and 9 matched-controls by using [3H]idazoxan (0.6-30 nM) in the presence of 10(-6) M (-)-adrenaline to prevent binding to alpha 2-adrenoceptors. In AD the density (Bmax) of I2-imidazoline sites was significantly higher (+63%) than in controls whereas no differences were apparent in affinity values (Kd). The results support the hypothesis that the I2 imidazoline site has a major location on glial (astrocyte) cells.
Ruiz
J
J
Department of Pharmacology, University of the Basque Country, Leioa, Spain.
Martín
I
I
Callado
L F
LF
Meana
J J
JJ
Barturen
F
F
García-Sevilla
J A
JA
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism* / Q000494:pharmacology; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D001345:Autoradiography; D004146:Dioxanes / Q000378:metabolism* / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D019329:Idazoxan; D054755:Imidazoline Receptors; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D017397:Prefrontal Cortex / Q000378:metabolism; D011955:Receptors, Drug / Q000378:metabolism*
D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D054755:Imidazoline Receptors; D011955:Receptors, Drug; D019329:Idazoxan; D004837:Epinephrine