Fluoxetine increases extracellular dopamine in the prefrontal cortex by a mechanism not dependent on serotonin: A comparison with citalopram

Laura Pozzi, Roberto Invernizzi, Claudio Garavaglia, Rosario Samanin

Research output: Contribution to journalArticlepeer-review

Abstract

Fluoxetine at 10 and 25 mg/kg increased (167 and 205%, respectively) the extracellular dopamine concentration in the prefrontal cortex, whereas 25 (but not 10) mg/kg citalopram raised (216%) dialysate dopamine. No compound modified dialysate dopamine in the nucleus accumbens. The effect of 25 mg/kg of both compounds on cortical extracellular dopamine was not significantly affected by 300 mg/kg p-chlorophenylalanine (PCPA) (fluoxetine, saline, 235%; PCPA, 230%; citalopram, saline, 179%; PCPA, 181%). PCPA depleted tissue and dialysate serotonin by ~90 and 50%, respectively, and prevented the effect of fluoxetine and citalopram on dialysate serotonin (fluoxetine, saline, 246%; PCPA, 110%; citalopram, saline, 155%; PCPA, 96%). Citalopram significantly raised extracellular serotonin from 0.1 to 100 μM (251-520%), whereas only 10 and 100 μM increased dialysate dopamine (143-231%). Fluoxetine similarly increased extracellular serotonin (98-336%) and dopamine (117-318%). PCPA significantly reduced basal serotonin and the effects of 100 μM fluoxetine (saline, 272%; PCPA, 203%) and citalopram (saline, 345%; PCPA, 258%) on dialysate serotonin but did not modify their effect on dopamine (fluoxetine, saline, 220%; PCPA, 202%; citalopram, saline, 191%; PCPA, 211%). The results clearly show that the effects of fluoxetine and of high concentrations of citalopram on extracellular dopamine do not depend on their effects on serotonin.

Original languageEnglish
Pages (from-to)1051-1057
Number of pages7
JournalJournal of Neurochemistry
Volume73
Issue number3
DOIs
Publication statusPublished - 1999

Keywords

  • Dopamine
  • Microdialysis
  • Nucleus accumbens
  • p-Chlorophenylalanine
  • Prefrontal cortex
  • Selective serotonin reuptake inhibitor
  • Serotonin

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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