title: Absence of alpha-methyldopamine in rat striatum after chronic administration of d-amphetamine.
abstract: Direct measurement by gas chromatography methane chemical ionization mass spectrometry of alpha-methyldopamine and alpha-methylnorepinephrine in rat striatum has shown the failure of these compounds to be accumulated in vivo after chronic administration of d-amphetamine despite the accumulation of alpha-methyltyramine, an immediate in vitro precursor. Further, both alpha-methyldopamine and alpha-methyltyramine accumulate in rat striatum after administration of alpha-methyltyrosine. These data suggest that, after administration of alpha-methyltyrosine, alpha-methyldopamine is formed via decarboxylation of alpha-methyldopa and not from hydroxylation of alpha-methyltyramine. Finally, our results indicate that alpha-methyldopamine does not play a role in the development of tolerance to d-amphetamine.
mesh_terms: D000818:Animals; D002849:Chromatography, Gas; D003342:Corpus Striatum / Q000378:metabolism*; D003653:Decarboxylation; D003846:Deoxyepinephrine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D003913:Dextroamphetamine / Q000378:metabolism*; D004298:Dopamine / Q000031:analogs & derivatives*; D008297:Male; D008750:Methyldopa / Q000378:metabolism; D008781:Methyltyrosines / Q000378:metabolism; D008771:Nordefrin / Q000378:metabolism; D051381:Rats; D013997:Time Factors; D019805:alpha-Methyltyrosine; D010136:p-Hydroxyamphetamine / Q000378:metabolism
chemical_list: D008781:Methyltyrosines; C023492:alpha-methyldopamine; D008750:Methyldopa; D019805:alpha-Methyltyrosine; D010136:p-Hydroxyamphetamine; D003846:Deoxyepinephrine; D008771:Nordefrin; D003913:Dextroamphetamine; D004298:Dopamine