Effects of depression, cigarette smoking, and age on monoamine oxidase B in amygdaloid nuclei.
Altered concentrations of dopamine transporter and D2/D3 receptors have been observed in the amygdaloid complex of subjects with major depression. These findings are suggestive of neurochemical abnormalities in the limbic dopamine system in depression. Monoamine oxidase-B (MAO-B) is a key enzyme in the catabolism of biogenic amines, including dopamine, and alterations in this enzyme may underlie dopaminergic abnormalities associated with depression. The specific binding of [(3)H]lazabemide to MAO-B was measured in the right amygdaloid complex of 15 major depressive subjects and 16 psychiatrically normal controls. Subjects of the two study groups were matched as close as possible for age, sex, and postmortem interval. Examination of the regional distribution of MAO-B revealed lower [(3)H]lazabemide binding to MAO-B in the lateral and basal nuclei of the amygdala and higher binding in the medial nucleus. A modest elevation in binding to MAO-B observed in all amygdaloid nuclei in major depressive subjects as compared to control subjects failed to reach statistical significance. A significant decrease in binding to MAO-B was observed when cigarette smokers were compared to nonsmoking subjects. The amount of MAO-B binding positively correlated with the age of subjects in all nuclei investigated. A decreased amount of MAO-B in smokers further validates the pharmacological effect of tobacco smoke on this enzyme.
Karolewicz
Beata
B
Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
Klimek
Violetta
V
Zhu
He
H
Szebeni
Katalin
K
Nail
Emily
E
Stockmeier
Craig A
CA
Johnson
Laurel
L
Ordway
Gregory A
GA
D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D000679:Amygdala / Q000378:metabolism* / Q000473:pathology; D001345:Autoradiography; D003865:Major Depressive Disorder / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000378:metabolism / Q000494:pharmacology; D010848:Picolinic Acids / Q000378:metabolism / Q000494:pharmacology; D011869:Radioligand Assay; D012189:Retrospective Studies; D012907:Smoking / Q000378:metabolism*; D014316:Tritium
D008996:Monoamine Oxidase Inhibitors; D010848:Picolinic Acids; D014316:Tritium; C059303:lazabemide; D008995:Monoamine Oxidase