Electrophysiological effects of monoamine oxidase inhibition on rat midbrain dopaminergic neurones: An in vitro study

Nicola B. Mercuri, Antonello Bonci, Antonio Siniscalchi, Alessandro Stefani, Paolo Calabresi, Giorgio Bernardi

Research output: Contribution to journalArticlepeer-review

Abstract

1. The effects of the inhibition of monoamine oxidase (MAO) type A and B have been evaluated on the spontaneous firing activity of the dopaminergic (principal) neurones of the rat midbrain intracellularly recorded from a slice preparation. 2. The non-specific MAO inhibitor, pargyline, superfused at a concentration of 10-100 μM, decreased or abolished the spontaneous firing discharge of the principal neurones in the subtantia nigra pars compacta and ventral tegmental area. This effect had a slow onset and appeared to be sustained. 3. The administration of the dopamine D(2/3) receptor antagonist, sulpiride (100-300 nM), antagonized the pargyline-induced effect, while the superfusion of the dopamine D 1 receptor antagonist, SCH 23390 (1-3 μM) did not counteract the induced inhibition of the firing rate. 4. The inhibitor for the MAO A, clorgyline (30-100 μM), reduced the firing rate of the dopaminergic neurones. A similar depressant effect was also observed when a MAO B inhibitor, deprenyl (30-100 μM), was applied. Lower concentrations of both drugs (300 nM-10 μM) did not produce consistent effects on neuronal discharge. 5. Our data suggest that only the blockade of both types of MAO enzymes favours the inhibitory action of endogenous dopamine on somato-dendritic D(2/3) autoreceptors.

Original languageEnglish
Pages (from-to)528-532
Number of pages5
JournalBritish Journal of Pharmacology
Volume117
Issue number3
Publication statusPublished - 1996

Keywords

  • -Sulpiride
  • Clorgyline
  • Deprenyl
  • Dopamine
  • Pargyline
  • SCH 23390
  • Spontaneous firing
  • Substantia nigra
  • Ventral tegmental area

ASJC Scopus subject areas

  • Pharmacology

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