Clinical Trial: Dopamine and Opioid Receptor Antagonists Reduce Cue-induced Reward Responding and Reward Impulsivity

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Dopamine D2/3- and μ-opioid Receptor Antagonists Reduce Cue-induced Reward Responding and Reward Impulsivity in Healthy Volunteers

Brief Summary: The purpose of this study is to determine how the dopamine and opioid system is involved in reward processing, specifically in cue-induced reward responding and reward impulsivity, using dopamine and opioid receptor antagonists in healthy participants. The investigators predict that particularly the dopamine challenge should alter cue-induced reward responding and reward impulsivity. Such effects would be of high interest for the treatment of disorders which involve impairments of reward processing such as addiction.

Detailed Summary:

In this study the investigators use amisulpride and naltrexone to elucidate what function the dopamine and opioid system have in the processing of reward. Amisulpride [Solian®; sanofi-aventis] is an atypical antipsychotic and acts as an antagonist at dopamine D2 and D3 (D2/D3) receptors with very high specificity. Amisulpride has been used in numerous past studies to study the role of dopamine in the brain, for example in studies on reinforcement learning, memory, and attentional bias in stimulant dependence. Naltrexone [Naltrexin®; OrPha Swiss GmbH] is an opioid antagonist and is clinically used in the management of alcohol and opioid dependence. It has been used to investigate the role of opioid in pain perception, taste detection and recognition, and smoking behavior. The investigators were interested in particular how amisulpride and naltrexone influence cue-induced reward responding and reward impulsivity.

Study Aims

A) Investigating the role of the dopamine system in cue-induced reward responding; B) Investigating the role of the dopamine system in reward impulsivity; C) Investigating the role of the opioid system in cue-induced reward responding; A) Investigating the role of the opioid system in reward impulsivity.

Study Design

This is a double-blind, randomized, placebo-controlled, between-subject blocker study. 121 participants received either placebo, the dopamine D2/D3 receptor antagonist amisulpride (400 mg), or the unselective opioid receptor antagonist naltrexone (50 mg), 3h before the experimental tasks. Subjective effects on mood were assessed by visual analogue scales (VAS). Cue-induced reward responding was measured using a standard Pavlovian-to-Instrumental Transfer (PIT) task, where participants
Sponsor: University of Zurich

Current Primary Outcome:

  • Cue-Induced Reward Responding Measure [ Time Frame: 1 day ]
    Measured using a Pavlovian-to-Instrumental Transfer Task
  • Reward Impulsivity Measure [ Time Frame: 1 day ]
    Measured using a Delay Discounting Task


Original Primary Outcome: Same as current

Current Secondary Outcome: Mood [ Time Frame: 1 day ]

Current Mood assessed by Visual Analog Scale (VAS)


Original Secondary Outcome: Same as current

Information By: University of Zurich

Dates:
Date Received: September 14, 2015
Date Started: February 2014
Date Completion:
Last Updated: September 22, 2015
Last Verified: September 2015