Antidepressant treatment facilitates dopamine release and drug seeking behavior in a genetic animal model of depression

Eur J Neurosci. 2009 Aug;30(3):485-92. doi: 10.1111/j.1460-9568.2009.06840.x. Epub 2009 Jul 15.

Abstract

Anhedonia and lack of motivation are core symptoms of depression. In contrast, hyper-motivation and euphoria characterize intoxicated states. In order to explore the relationship between these two behavioral states we examined cocaine self-administration tasks in an animal model of depression [Flinders Sensitive Line (FSL) rats]. We found that FSL rats exhibit sub-sensitivity in their cocaine-seeking behavior, which was normalized following a chronic treatment with the antidepressant desipramine. However, when the cocaine dosage was increased, FSL rats demonstrated a similar cocaine-seeking behavior to that of controls. In light of dopamine's central role in modulating cocaine reinforcement, we examined dopaminergic neurotransmission in the nucleus accumbens, a brain region implicated in the rewarding and hedonic effects of substances of misuse. FSL rats exhibited low but dose-dependent increases in extracellular levels of dopamine in the nucleus accumbens after acute intravenous cocaine injection. Furthermore, by using the dopamine transporter blocker GBR-12909 we were able to demonstrate that the low extracellular dopamine levels, observed in FSL rats, were a consequence of low dopamine release in the nucleus accumbens, as opposed to the possibility of increased uptake. Treatment of FSL rats with the antidepressant desipramine raised cocaine- and GBR-12909-induced dopamine release to the level of controls. This treatment also resulted in increased cocaine-seeking behavior.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antidepressive Agents / pharmacology*
  • Autoradiography
  • Behavior, Addictive / drug therapy
  • Behavior, Addictive / metabolism
  • Behavior, Addictive / physiopathology
  • Behavior, Animal / drug effects
  • Cocaine / pharmacology
  • Depression / drug therapy*
  • Depression / metabolism
  • Depression / physiopathology
  • Disease Models, Animal
  • Dopamine / metabolism*
  • Dopamine Uptake Inhibitors / pharmacology
  • Microdialysis
  • Nucleus Accumbens / drug effects*
  • Nucleus Accumbens / metabolism
  • Rats

Substances

  • Antidepressive Agents
  • Dopamine Uptake Inhibitors
  • Cocaine
  • Dopamine