Carrier-mediated release of serotonin by 3,4-methylenedioxymethamphetamine: implications for serotonin-dopamine interactions.
In vivo microdialysis was used to determine whether the 3,4-methylenedioxymethamphetamine (MDMA)-induced release of serotonin (5-HT) in vivo involves a carrier-mediated process and to investigate further the state-dependent interaction between 5-HT and dopamine. MDMA produced a dose-dependent increase in the extracellular concentration of 5-HT in the striatum and prefrontal cortex that was attenuated by treatment with fluoxetine but not by tetrodotoxin. Suppression by fluoxetine of the MDMA-induced release of 5-HT was accompanied by a suppression of the MDMA-induced release of dopamine. Administration of MDMA to rats treated with carbidopa and L-5-hydroxytryptophan resulted in a synergistic elevation of the extracellular concentration of 5-HT that was much greater than that produced by either treatment alone. The MDMA-induced release of dopamine by MDMA also was potentiated in 5-hydroxytryptophan-treated rats. These data are consistent with the view that MDMA increases the extracellular concentration of 5-HT by facilitating carrier-mediated 5-HT release, which can be enhanced greatly under conditions in which 5-HT synthesis is stimulated. Moreover, these data are supportive of a state-dependent, stimulatory role of 5-HT in the regulation of dopamine release.
Gudelsky
G A
GA
Department of Psychiatry, Case Western Reserve University, Cleveland, Ohio, USA.
Nash
J F
JF
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D002230:Carbidopa / Q000494:pharmacology; D002352:Carrier Proteins / Q000502:physiology*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004357:Drug Synergism; D005473:Fluoxetine / Q000494:pharmacology; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000502:physiology*; D026901:Membrane Transport Proteins; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology* / Q000633:toxicity; D009419:Nerve Tissue Proteins; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D018490:Serotonin Agents / Q000494:pharmacology*; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D006916:5-Hydroxytryptophan; D002230:Carbidopa; D002352:Carrier Proteins; D004298:Dopamine; D005473:Fluoxetine; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D009419:Nerve Tissue Proteins; D012701:Serotonin; D018490:Serotonin Agents; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors; D013779:Tetrodotoxin; C493232:Slc6a4 protein, rat