Striatal dopamine metabolism in monoamine oxidase B-deficient mice: a brain dialysis study.
We have studied striatal dopamine (DA) metabolism in monoamine oxidase (MAO) B-deficient mice using brain microdialysis. Baseline DA levels were similar in wild-type and knock-out (KO) mice. Administration of a selective MAO A inhibitor, clorgyline (2 mg/kg), increased DA levels and decreased levels of its metabolites in all mice, but a selective MAO B inhibitor, l-deprenyl (1 mg/ kg), had no effect. Administration of 10 and 50 mg/kg L-DOPA, the precursor of DA, increased the levels of DA similarly in wild-type and KO mice. The highest dose of L-DOPA (100 mg/kg) produced a larger increase in DA in KO than wild-type mice. This difference was abolished by pretreating wild-type mice with l-deprenyl. These results suggest that in mice, DA is only metabolized by MAO A under basal conditions and by both MAO A and B at high concentrations. This is in contrast to the rat, where DA is always metabolized by MAO A regardless of concentration.
Fornai
F
F
Department of Human Morphology and Applied Biology, University of Pisa, Italy.
Chen
K
K
Giorgi
F S
FS
Gesi
M
M
Alessandri
M G
MG
Shih
J C
JC
D000818:Animals; D001923:Brain Chemistry; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017551:Microdialysis; D008995:Monoamine Oxidase / Q000172:deficiency* / Q000235:genetics; D010627:Phenethylamines / Q000378:metabolism; D051381:Rats; D012642:Selegiline / Q000494:pharmacology; D013045:Species Specificity
D010627:Phenethylamines; D012642:Selegiline; C029261:phenethylamine; D007980:Levodopa; D008995:Monoamine Oxidase; D004298:Dopamine