Biphasic and region-specific MAO-B response to aging in normal human brain.
Variations of monoamine oxidases (MAO) A and B were studied during aging in 27 human subjects (age range 17-93 years) in 18 brain structures of temporal cortex, frontal gyrus, hippocampal formation, striatum, cerebellum, and brainstem. [3H]Ro41-1049 and [3H]lazabemide were used as selective radioligands to image and quantify MAO-A and MAO-B respectively by enzyme autoradiography. Postmortem delay or time of tissue storage did not affect MAO-A or MAO-B levels. There was, moreover, no evidence of sexual dimorphism. A marked age-related increase in MAO-B was observed in most structures. This increase started at the age of 50-60 years. Before this age, MAO-B levels were constant in all structures studied. MAO-B-rich senile plaques were observed in some cortical areas but they did not significantly influence the age-related MAO-B increase. Surprisingly, no age-related MAO-B changes were observed in the substantia nigra. In contrast to MAO-B, no clear age-related changes in MAO-A were observed, indicating an independent regulation of the two isoenzymes, also suggested by the cross-correlation analysis of these data.
Saura
J
J
Biochemistry Unit, School of Medicine, University of Barcelona, Spain.
Andrés
N
N
Andrade
C
C
Ojuel
J
J
Eriksson
K
K
Mahy
N
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001345:Autoradiography; D001921:Brain / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology; D010848:Picolinic Acids / Q000493:pharmacokinetics / Q000494:pharmacology; D012727:Sex Characteristics; D013844:Thiazoles / Q000493:pharmacokinetics / Q000494:pharmacology
D008996:Monoamine Oxidase Inhibitors; D010848:Picolinic Acids; D013844:Thiazoles; C063456:Ro 41-1049; C059303:lazabemide; D008995:Monoamine Oxidase