The neurotoxic mechanisms of amphetamine: Step by step for striatal dopamine depletion

Neurosci Lett. 2017 Feb 3;639:185-191. doi: 10.1016/j.neulet.2017.01.002. Epub 2017 Jan 6.

Abstract

Amphetamine (AMPH) is a commonly abused psychostimulant that induces neuronal cell death/degeneration in humans and experimental animals. Although multiple neurotoxic mechanisms of AMPH have been intensively investigated, the interplay between these mechanisms has remained elusive. In this study, we used a rat model of AMPH-induced long-lasting striatal dopamine (DA) depletion and identified mechanisms of neurotoxicity, energy failure, excitotoxicity, and oxidative stress. Pretreatment with nicotinamide (NAM, a co-factor for the electron transport chain) blocked AMPH-induced free radical formation, energy failure, and striatal DA decrease. Also, MK-801 (a NMDA receptor antagonist) blocked AMPH-induced free radical formation and striatal DA but not energy failure decrease, indicating excitotoxicity may occur before free radical formation and after energy failure. Thus, these results show that during AMPH intoxication, energy failure, excitotoxicity, and free radical formation are orchestrated consecutively to mediate the depletion of striatal DA.

Keywords: Amphetamine; Dopamine; Energy failure; Excitotoxicity; Free radicals; Striatum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphetamine / pharmacology*
  • Animals
  • Central Nervous System Stimulants / pharmacology
  • Corpus Striatum / drug effects*
  • Dextroamphetamine / pharmacology
  • Dizocilpine Maleate / pharmacology
  • Dopamine / metabolism*
  • Male
  • Neurotoxicity Syndromes / metabolism*
  • Niacinamide / pharmacology*
  • Rats, Sprague-Dawley

Substances

  • Central Nervous System Stimulants
  • Niacinamide
  • Dizocilpine Maleate
  • Amphetamine
  • Dextroamphetamine
  • Dopamine