Simultaneous increases of extracellular monoamines in microdialysates from hypothalamus of conscious rats by duloxetine, a dual serotonin and norepinephrine uptake inhibitor

Eric A. Engleman, Kenneth W. Ferry, Douglas A. Mayle, David T. Wong

Research output: Contribution to journalArticle

66 Scopus citations

Abstract

Duloxetine (LY248686, [+]-N-methyl-3-(l- napthalenyloxy)-2-thiophene-propanamine) is a potent dual inhibitor of serotonin (5-hydroxytryptamine, 5-HT) and norepinephrine (NE) uptake in hypothalamus and cerebral cortex of rat brain (Wong et al. 1993; Fuller et al. 1994). Consistent with the dual mechanisms of inhibiting 5-HT and NE uptake, duloxetine at 15 mg/kg IP produced large increases in extracellular levels of 5-HT (250%) and NE (1, 100%) 30 minutes after systemic administration. Levels of 3-methoxy-4-hydroxy- phenylethyleneglycol (MHPG) and 5-hydroxyindoleacetic acid (5-HlAA), metabolites of NE and 5-HT, respectively, were reduced, whereas those of dopamine (DA) and its metabolite 3, 4-dihydroxyphenylacetic acid (DOPAC) were not significantly altered. Duloxetine at 7 mgikg produced less pronounced increases while no consistent effects were observed at 4 mgikg. In this dose range, duloxetine inhibited 5-HT uptake in platelets ex vivo without inhibiting striatal dopamine (DA) uptake. In the present study we also found that the primary amine (a racemate) of duloxetine is about one-fourth as active as duloxetine to inhibit 5-HT and NE uptake. The potential primary amine metabolite of duloxetine might contribute, in part, to the inhibition of 5-HT and NE uptake in ihvo. Thus the ability to produce robust increases of extracellular 5-HT and NE levels suggests that duloxetine may potentially be a highly effective antidepressant agent.

Original languageEnglish (US)
Pages (from-to)287-295
Number of pages9
JournalNeuropsychopharmacology
Volume12
Issue number4
DOIs
StatePublished - Jul 1995
Externally publishedYes

Keywords

  • High-performance liquid chromatography
  • Hypothalamus
  • Microdialysis
  • Monoamines
  • Rats
  • Uptake inhibitors

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health

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