Euphorigenic doses of cocaine reduce [123I]β-CIT SPECT measures of dopamine transporter availability in human cocaine addicts

Robert T. Malison, S. E. Best, E. McCance, M. Laruelle, R. M. Baldwin, J. S. Seibyl, L. H. Price, T. R. Kosten, R. B. Innis, P. B. Hoffer, S. S. Zoghbi, E. A. Wallace

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

The in vivo potency of euphorigenic doses of intravenous cocaine for displacing [123I]β-CIT ([123I]2 β-carbomethoxy-3 β-(4-iodophenyl)tropane) binding to striatal dopamine transporters (DAT) was assessed in human cocaine addicts using single photon emission computed tomography (SPECT). Cocaine-dependent subjects (n=6) were injected with [123I]β-CIT and imaged 24 h later under equilibrium conditions. Sequential cocaine infusions (0.28±0.03 and 0.56±0.07 mg/kg) produced significant (P<0.0005) reductions in the specific to non-specific equilibrium partition coefficient, V3″ (6±6 and 17±3%), a measure proportional to DAT binding potential. Regression analysis of the logit transformed data enabled reliable determination of the Hill coefficient (0.51) and 50% displacement (ED50) dose of cocaine (2.8 mg/kg). These preliminary data suggest that cocaine produces behavioral effects in humans at measurable levels of DAT occupancy.

Original languageEnglish (US)
Pages (from-to)358-362
Number of pages5
JournalPsychopharmacology
Volume122
Issue number4
DOIs
StatePublished - Dec 1995

Keywords

  • Cocaine
  • Dopamine transporter
  • Medication development
  • [I]β-CIT

ASJC Scopus subject areas

  • Pharmacology

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