Tyrosine augments acute clozapine- but not haloperidol-induced dopamine release in the Medial Prefrontal Cortex of the rat: An in vivo microdialysis study

George E. Jaskiw, Keith A. Collins, Elizabeth A. Pehek, Bryan K. Yamamoto

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Tyrosine availability can influence dopamine (DA) synthesis in highly electrophysiologically active DAergic neurons, such as those innervating the medial prefrontal cortex (MPFC). Whether tyrosine concentrations can also affect MPFC extracellular DA concentrations, measured in vivo, is not known. Since clozapine preferentially activates mesocortical DA neurons, we posited that tyrosine administration to a clozapine-pretreated rat would enhance the clozapine-induced augmentation of MPFC extracellular DA concentrations. Tyrosine alone (25-50mg/kg IP) did not affect mesocortical or striatal extracellular DA concentrations measured by in vivo microdialysis. Given 30 minutes after clozapine (10 mg/kg), tyrosine (50 mg/kg) significantly prolonged the clozapine-induced increase in MPFC extracellular DA concentrations but had no effect in the striatum. In contrast, tyrosine (50 mg/kg) significantly prolonged the haloperidol (1 mg/kg) induced increase in striatal extracellular DA concentrations but had no effect in the MPFC. These data constitute the first in vivo evidence that administration of tyrosine can selectively potentiate the clozapine-evoked increase in mesocortical extracellular DA concentrations.

Original languageEnglish (US)
Pages (from-to)149-156
Number of pages8
JournalNeuropsychopharmacology
Volume25
Issue number1
DOIs
StatePublished - Jun 11 2001
Externally publishedYes

Keywords

  • Antipsychotics
  • Clozapine
  • Dopamine
  • Microdialysis
  • Schizophrenia
  • Tyrosine

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health

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