Styrene inhibits monoamine oxidase A, but not monoamine oxidase B in monkey brain mitochondria.
The effects of styrene on mitochondrial monoamine oxidase (MAO) activity in rat and monkey brains were compared in vitro. After preincubation at 25 degrees C for 20 min with 1 mM styrene monomer MAO-A activity in monkey brain was inhibited potently using 5-HT (for MAO-A substrate), but MAO-B activity in monkey brain and platelets were slightly inhibited using beta-PEA (for MAO-B substrate). Styrene monomer also competitively inhibited MAO-A activity in a dose-dependent manner. MAO-A in monkey brain was inhibited by styrene in ascending order of potency: styrene trimer>styrene dimer>styrene monomer. In contrast styrene monomer slightly inhibited both MAO-A and MAO-B activities in rat brain mitochondria. In the present study styrene monomer potently inhibits MAO-A activity, but not MAO-B activity, in monkey brain mitochondria in vitro. These results indicate the inhibiting action of styrene differs depending on animal species and MAO isoforms.
Egashira
T
T
Department of Pharmacology, Oita Medical University, 1-1, Idaigaoka, Hasama-machi, 879-5593, Oita, Japan. egacy@oita-med.ac.jp
Takayama
F
F
Sakai
K
K
Yamanaka
Y
Y
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D008251:Macaca; D008297:Male; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology; D008995:Monoamine Oxidase / Q000187:drug effects* / Q000378:metabolism; D010627:Phenethylamines / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism; D020058:Styrene / Q000494:pharmacology*; D013379:Substrate Specificity
D010627:Phenethylamines; C029261:phenethylamine; D012701:Serotonin; D020058:Styrene; D008995:Monoamine Oxidase