Blocking TRPV1 in nucleus accumbens inhibits persistent morphine conditioned place preference expression in rats

PLoS One. 2014 Aug 13;9(8):e104546. doi: 10.1371/journal.pone.0104546. eCollection 2014.

Abstract

The function of TRPV1 (transient receptor potential vanilloid subfamily, member 1) in the central nervous system is gradually elucidated. It has been recently proved to be expressed in nucleus accumbens (NAc), a region playing an essential role in mediating opioid craving and taking behaviors. Based on the general role of TRPV1 antagonist in blocking neural over-excitability by both pre- and post-synaptic mechanisms, TRPV1 antagonist capsazepine (CPZ) was tested for its ability to prohibit persistent opioid craving in rats. In the present study, we assessed the expression of TRPV1 in nucleus accumbens and investigated the effect of CPZ in bilateral nucleus accumbens on persistent morphine conditioned place preference (mCPP) in rats. We also evaluated the side-effect of CPZ on activity by comparing cross-beam times between groups. We found that morphine conditioned place preference increased the TRPV1 expression and CPZ attenuated morphine conditioned place preference in a dose-dependent and target-specific manner after both short- and long-term spontaneous withdrawal, reflected by the reduction of the increased time in morphine-paired side. CPZ (10 nM) could induce prolonged and stable inhibition of morphine conditioned place preference expression. More importantly, CPZ did not cause dysfunction of activity in the subjects tested, which indicates the inhibitory effect was not obtained at the sacrifice of regular movement. Collectively, these results indicated that injection of TRPV1 antagonist in nucleus accumbens is capable of attenuating persistent morphine conditioned place preference without affecting normal activity. Thus, TRPV1 antagonist is one of the promising therapeutic drugs for the treatment of opioid addiction.

Publication types

  • Research Support, Non-U.S. Gov't
  • Retracted Publication

MeSH terms

  • Animals
  • Blotting, Western
  • Capsaicin / analogs & derivatives*
  • Capsaicin / pharmacology
  • Craving / drug effects*
  • Dose-Response Relationship, Drug
  • Male
  • Microscopy, Immunoelectron
  • Morphine
  • Nucleus Accumbens / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Spatial Behavior / drug effects*
  • TRPV Cation Channels / antagonists & inhibitors*
  • TRPV Cation Channels / metabolism*

Substances

  • TRPV Cation Channels
  • Trpv1 protein, rat
  • Morphine
  • capsazepine
  • Capsaicin

Grants and funding

This work is supported by National Natural Science Foundation of China (31070940 to GDG, 31100778 to LJH), Military 12th Five-year Program of China (BWS11J006 to GZX), Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (SRFROCS1711 to LJH), Tangdu Outstanding Talents Surporting Project (Tangdu5084 to LJH) and China Postdoctoral Science Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.