Opioid Modulation and Neural Reward Activation in Healthy Adults

This is a double blind study of the effects of opioid antagonism on the brain's reward response. The investigators will recruit participants to undergo two scans, one on active medication and one on placebo. During the scan, the investigators will assess reward.

Study Overview

• Status: Completed
• Conditions: Alcohol Drinking; Opioid Use, Unspecified
• Intervention / Treatment: Drug: Naltrexone; Other: Placebo

Detailed Description

The study will employ a crossover design. The study will use the monetary incentive delay task during functional MRI to assess reward. This task presents participants with cues indicating whether they are playing to win $5, win $0, or to avoid losing $5. This task has been well-validated to elicit activation in a key reward response area of the brain called the ventral striatum.

• Study Type: Interventional
• Enrollment (Actual): 13
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Aurora, Colorado, United States, 80045
      • University of Colorado Anschutz Medical Campus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Between 18 and 35 years of age,
• Is a moderate drinker (i.e. consumes 1-14 drinks/week for males, or 1-7 drinks/week for females).

Exclusion Criteria:

• Non-drinker
• Positive result on urine drug screen or breathalyzer at the start of any study visit
• Inability to complete MRI (e.g. presence of ferromagnetic objects in body)
• Current use of medications that alter the hemodynamic response such as insulin
• History of trauma resulting in loss of consciousness longer than 15 minutes
• Currently taking opioid medications
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Placebo, Then Naltrexone; Participants first received placebo capsules each day in a blister pack for 5 days. After a washout period of at least 3 days, they then received naltrexone capsules (matching placebo capsules) at 25mg/day for days 1 and 2 and then 50mg/day for days 3-5 for 5 days.	Drug: Naltrexone; Naltrexone is an opioid antagonist with primary action at the mu opioid receptor.; Other: Placebo; Placebo will be used to control for expectancy effects
Experimental: Naltrexone, Then Placebo; Participants first received naltrexone capsules each day in a blister pack for 5 days. Days 1 and 2 were at 25mg/day, and days 3-5 were at 50mg/day. After a washout period of at least 3 days, they then received placebo capsules (matching naltrexone capsules) for 5 days.	Drug: Naltrexone; Naltrexone is an opioid antagonist with primary action at the mu opioid receptor.; Other: Placebo; Placebo will be used to control for expectancy effects

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Brain Activation to Reward Between Placebo and Active Medication	Percent signal change relative to baseline in the nucleus accumbens during cue to win $5 as assessed during functional MRI. Higher values of percent signal change indicate greater activation to reward. We will compare the active medication condition to the placebo, establishing whether there is a difference between the conditions.	one week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Alcohol Value	Maximum alcohol expenditure, or Omax, is the maximum amount of money that a person will pay for alcohol in a hypothetical alcohol consumption task called the "Alcohol Purchase Task". Higher values of Omax indicate that a person values consuming alcohol at a greater level.	one week
Brain Activation to Emotion Regulation	Percent signal change from baseline in the amygdala during trials to regulate emotion relative to trials to passively experience emotion during a functional MRI scan. Cues will be negative images, and instructions will be either "decrease" or "look".	one week

Collaborators and Investigators

• Sponsor: University of Colorado, Denver
• Investigators: Principal Investigator: Joshua Gowin, PhD, University of Colorado - Anschutz Medical Campus

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2021
• Primary Completion (Actual): April 18, 2022
• Study Completion (Actual): April 18, 2022

Study Registration Dates

• First Submitted: April 8, 2021
• First Submitted That Met QC Criteria: April 19, 2021
• First Posted (Actual): April 22, 2021

Study Record Updates

• Last Update Posted (Actual): November 28, 2023
• Last Update Submitted That Met QC Criteria: November 6, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Drinking Behavior; Alcohol Drinking; Physiological Effects of Drugs; Peripheral Nervous System Agents; Sensory System Agents; Narcotic Antagonists; Alcohol Deterrents; Naltrexone
• Other Study ID Numbers: 21-2886

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The investigators would either upload to an online repository or share directly with individuals wishing to access it.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes