title: Differential effects of D- and L-amphetamine and methylphenidate on rat striatal dopamine biosynthesis.
abstract: Methylphenidate and the optical isomers of amphetamine have differential effects, in vivo and in vitro on rat striatal synaptosomal dopamine (DA) biosynthesis. Whereas the systemic administration of D- or L-amphetamine produces a dose-dependent decrease in synaptosomal DA synthesis, with ED50's of 1.1 and 3.5 mg/kg, respectively, methylphenidate, at doses which produce comparable degrees of stereotypes behavior, has no effect on this measure of DA biosynthesis. In vitro, D- and L-amphetamine exhibit a three-fold difference in ED50's (1 times 10-minus 6 M and 3 times 10-minus 6 M, respectively) with respect to both activation of striatal synpatosomal DA synthesis, and to reversal of reserpine-induced inhibition of DA synthesis. In contrast, although in vitro methylphenidate can partially activate DA synthesis, it does not overcome the reserpeine-induced inhibition. The data are discussed in terms of the possible differential mechanisms by which these two types of stimulants may exert their effects on sterotypy.
mesh_terms: D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000096:biosynthesis*; D066298:In Vitro Techniques; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012110:Reserpine / Q000494:pharmacology; D013574:Synaptosomes / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D008774:Methylphenidate; D014443:Tyrosine; D012110:Reserpine; D000661:Amphetamine; D003913:Dextroamphetamine; D004298:Dopamine