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Restoration of 3,4-methylenedioxymethamphetamine-induced 5-HT depletion by the administration of

X Wang1, M H Baumann, C M Dersch

  • 1Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, P.O. Box 5180, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.

Neuroscience
|July 17, 2007
PubMed
Abstract

Insights

High-dose 3,4-Methylenedioxymethamphetamine (MDMA) significantly reduces serotonin transporter (SERT) binding, but a substantial number of serotonin (5-HT) nerve terminals remain functional. Treatment with 5-hydroxytryptophan/benserazide (5-HTP-B) can restore depleted brain 5-HT levels.

Area of Science:

  • Neuroscience
  • Pharmacology
  • Toxicology

Background:

  • 3,4-Methylenedioxymethamphetamine (MDMA) causes lasting reductions in brain serotonin (5-HT) content and 5-HT transporter (SERT) binding.
  • Existing data suggest MDMA impairs 5-HT transmission while leaving 5-HT nerve terminals intact.

Purpose of the Study:

  • To investigate the functional integrity of 5-HT nerve terminals after high-dose MDMA exposure.
  • To determine if 5-HT precursor administration can restore MDMA-induced 5-HT depletions.

Main Methods:

  • Rats received high-dose MDMA (three injections of 7.5 mg/kg) or saline.
  • SERT binding and [(3)H]5-HT uptake were measured under varying NaCl concentrations.
  • MDMA-treated rats received 5-hydroxytryptophan/benserazide (5-HTP-B) to assess 5-HT restoration.

Main Results:

  • MDMA reduced SERT binding by 90% under standard conditions, but this effect was attenuated in low NaCl.
  • Brain 5-HT levels in the caudate and hippocampus were reduced to approximately 35% of control.
  • 5-HTP-B administration significantly increased 5-HT levels in MDMA-treated rats.

Conclusions:

  • A significant population of functionally intact 5-HT nerve terminals survive high-dose MDMA treatment.
  • The observed reduction in SERT binding is dependent on in vitro assay conditions.
  • 5-HTP-B effectively restores MDMA-induced brain 5-HT depletion, indicating potential clinical utility for abstinent MDMA users.

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