Involvement of dopamine D2 receptors in apomorphine-induced facilitation of forebrain serotonin output

Anna Mendlin, Francisco J. Martín, Barry L. Jacobs

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


The effect of systemic administration of the nonselective dopamine receptor agonist apomorphine on efflux of serotonin (5-hydroxytryptamine, 5-HT) in striatum and hippocampus of freely moving rats was examined using in vivo microdialysis. 5-HT efflux was increased by a moderate dose of apomorphine sufficient for a postsynaptic dopaminergic effect (0.5 mg/kg, s.c.), but not by a lower dose (0.1 mg/kg, s.c.), that acts preferentially on presynaptic dopamine receptors. This effect was blocked by a dopamine D2 receptor antagonist raclopride, administered either systemically or locally into striatum, but not by a 5-HT(1A) receptor antagonist N-{2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl}-N-(2-pyridinyl) cyclohexanecarboxamide 3HCl (WAY-100635). This indicates that dopamine D2 receptors, and not 5-HT(1A) receptors, mediate the facilitatory effect of apomorphine, and that this effect occurs at the nerve terminal level. Behavioral effects of apomorphine outlasted the concomitant changes in 5-HT efflux, suggesting that these changes resulted from dopaminergic receptor activation, rather than from the drug-induced behavioral arousal. Copyright (C) 1998 Elsevier Science B.V. All rights reserved.

Original languageEnglish (US)
Pages (from-to)291-298
Number of pages8
JournalEuropean Journal of Pharmacology
Issue number3
StatePublished - Jun 26 1998

All Science Journal Classification (ASJC) codes

  • Pharmacology


  • 5-HT (5-hydroxytryptamine, serotonin)
  • 5-HT(1A) autoreceptor
  • Dopamine
  • Dopamine D receptor
  • Microdialysis
  • Stereotypy


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