| pubmed-article:1126362 | pubmed:abstractText | 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. | lld:pubmed |
