title: A new metabolically trapped agent by brain monoamine oxidase: N-methyl labeled (14C) N-methylphenylethylamine (14C-MPEA).
abstract: A new type of metabolically trapped agent for measuring regional brain function was designed and evaluated. N-methylphenylethylamine (14C-MPEA) was synthesized with trifluoroacetylphenylethylamine and 14C-methyl iodide. A high concentration of 14C-MPEA accumulated in mouse brain 1 min after injection, and radioactivities in the brain remained for a long period. By radiochemical analysis, it was found 14C-MPEA was metabolized in the brain to 14C-methylamine. 14C-methylamine was trapped by the blood-brain barrier because of its cationic charge at physiological pH. When the mouse was pretreated with a MAO inhibitor (pargyline hydrochloride 100 mg/kg IP) the radioactivity was rapidly excreted from the brain with a half-life of about 45 min. These results indicate that 11C-MPEA has potential for the measurement of brain MAO activity.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D001923:Brain Chemistry; D055598:Chemical Phenomena; D002621:Chemistry; D008297:Male; D008694:Methamphetamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008995:Monoamine Oxidase / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: C027141:N-methylphenethylamine; D008694:Methamphetamine; D008995:Monoamine Oxidase