Temporal Rewiring of Striatal Circuits Initiated by Nicotine

Neuropsychopharmacology. 2016 Dec;41(13):3051-3059. doi: 10.1038/npp.2016.118. Epub 2016 Jul 8.

Abstract

Drug addiction has been conceptualized as maladaptive recruitment of integrative circuits coursing through the striatum, facilitating drug-seeking and drug-taking behavior. The aim of this study was to define temporal neuroadaptations in striatal subregions initiated by 3 weeks of intermittent nicotine exposure followed by protracted abstinence. Enhanced rearing activity was assessed in motor activity boxes as a measurement of behavioral change induced by nicotine (0.36 mg/kg), whereas electrophysiological field potential recordings were performed to evaluate treatment effects on neuronal activity. Dopamine receptor mRNA expression was quantified by qPCR, and nicotine-induced dopamine release was measured in striatal subregions using in vivo microdialysis. Golgi staining was performed to assess nicotine-induced changes in spine density of medium spiny neurons. The data presented here show that a brief period of nicotine exposure followed by abstinence leads to temporal changes in synaptic efficacy, dopamine receptor expression, and spine density in a subregion-specific manner. Nicotine may thus initiate a reorganization of striatal circuits that continues to develop despite protracted abstinence. We also show that the response to nicotine is modulated in previously exposed rats even after 6 months of abstinence. The data presented here suggests that, even though not self-administered, nicotine may produce progressive neuronal alterations in brain regions associated with goal-directed and habitual performance, which might contribute to the development of compulsive drug seeking and the increased vulnerability to relapse, which are hallmarks of drug addiction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Corpus Striatum / drug effects*
  • Disease Models, Animal
  • Dopamine / metabolism
  • Goals
  • In Vitro Techniques
  • Locomotion / drug effects
  • Male
  • Microdialysis
  • Nerve Net / drug effects*
  • Nerve Net / ultrastructure
  • Nicotine / pharmacology*
  • Nicotinic Agonists / pharmacology*
  • Patch-Clamp Techniques
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Receptors, Dopamine / genetics
  • Receptors, Dopamine / metabolism
  • Silver Staining
  • Statistics, Nonparametric
  • Time Factors
  • Tobacco Use Disorder / pathology*

Substances

  • Nicotinic Agonists
  • RNA, Messenger
  • Receptors, Dopamine
  • Nicotine
  • Dopamine