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Altered brain serotonin homeostasis and locomotor insensitivity to 3, 4-methylenedioxymethamphetamine ("Ecstasy") in serotonin transporter-deficient mice.

The sodium-dependent, high affinity serotonin [5-hydroxytryptamine (5-HT)] transporter (5-HTT) provides the primary mechanism for inactivation of 5-HT after its release into the synaptic cleft. To further evaluate the function of the 5-HTT, the murine gene was disrupted by homologous recombination. Despite evidence that excess extracellular 5-HT during embryonic development, including that produced by drugs that inhibit the 5-HTT, may lead to severe craniofacial and cardiac malformations, no obvious developmental phenotype was observed in the 5-HTT-/- mice. High affinity [3H]5-HT uptake was completely absent in 5-HTT-/- mice, confirming a physiologically effective knockout of the 5-HTT gene. 5-HTT binding sites labeled with [125I] 3 beta-(4'-iodophenyl)tropan-2 beta-carboxylic acid methyl ester were reduced in a gene dose-dependent manner, with no demonstrable binding in 5-HTT-/- mutants. In adult 5-HTT-/- mice, marked reductions (60-80%) in 5-HT concentrations were measured in several brain regions. While (+)-amphetamine-induced hyperactivity did not differ across genotypes, the locomotor enhancing effects of (+)-3, 4-methylenedioxymethamphetamine, a substituted amphetamine that releases 5-HT via a transporter-dependent mechanism, was completely absent in 5-HTT-/- mutants. Together, these data suggest that the presence of a functional 5-HTT is essential for brain 5-HT homeostasis and for 3,4-methylenedioxymethamphetamine-induced hyperactivity.

Pubmed ID: 9547354


  • Bengel D
  • Murphy DL
  • Andrews AM
  • Wichems CH
  • Feltner D
  • Heils A
  • Mössner R
  • Westphal H
  • Lesch KP


Molecular pharmacology

Publication Data

April 6, 1998

Associated Grants


Mesh Terms

  • Animals
  • Autoradiography
  • Brain Chemistry
  • Carrier Proteins
  • Female
  • Gene Targeting
  • Genotype
  • Homeostasis
  • Locomotion
  • Male
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred Strains
  • Mice, Knockout
  • Microinjections
  • N-Methyl-3,4-methylenedioxyamphetamine
  • Nerve Tissue Proteins
  • Serotonin
  • Serotonin Plasma Membrane Transport Proteins