Dopamine uptake inhibitors but not dopamine releasers induce greater increases in motor behavior and extracellular dopamine in adolescent rats than in adult male rats.

Journal Article

Most life-long drug addiction begins during adolescence. Important structural and functional changes in brain occur during adolescence and developmental differences in forebrain dopamine systems could mediate a biologic vulnerability to drug addiction during adolescence. Studies investigating age differences in psychostimulant responses have yielded mixed results, possibly because of different mechanisms for increasing extracellular dopamine. Recent research from our laboratory suggests that adolescent dopamine systems may be most affected by selective dopamine uptake inhibitors. We investigated age-related behavioral responses to acute administration of several dopamine uptake inhibitors [methylphenidate, 1-{2-[bis-(4-fluorophenyl)methoxy]ethyl}-4-(3-phenylpropyl)piperazine (GBR12909), and nomifensine] and releasing agents [amphetamine and methylenedioxymethamphetamine (MDMA)] in adolescent and adult male rats. Methylphenidate and amphetamine effects on stimulated dopamine efflux were determined using fast-scan cyclic voltammetry in vivo. Dopamine uptake inhibitors but not dopamine releasing agents induced more locomotion and/or stereotypy in adolescent relative to adult rats. MDMA effects were greater in adults at early time points after dosing. Methylphenidate but not amphetamine induced much greater dopamine efflux in periadolescent relative to adult rats. Periadolescent male rats are particularly sensitive to psychostimulants that are DAT inhibitors but are not internalized and do not release dopamine. Immaturity of DAT and/or DAT associated signaling systems in adolescence specifically enhances behavioral and dopaminergic responses in adolescence.

Full Text

Duke Authors

Cited Authors

  • Walker, QD; Morris, SE; Arrant, AE; Nagel, JM; Parylak, S; Zhou, G; Caster, JM; Kuhn, CM

Published Date

  • October 2010

Published In

Volume / Issue

  • 335 / 1

Start / End Page

  • 124 - 132

PubMed ID

  • 20605908

Electronic International Standard Serial Number (EISSN)

  • 1521-0103

Digital Object Identifier (DOI)

  • 10.1124/jpet.110.167320

Language

  • eng

Conference Location

  • United States