Health TrialsbyHealthPanel

The Role of Brain Dopamine in Chronic Pain

ConditionChronic Pain
Trial statusRecruiting
Trial phasePhase 2
Trial typeInterventional
Biological sexAll
Age18+
SponsorUniversity of Rochester

About this trial

Chronic pain is associated with plasticity in the brain limbic system composed mainly of the amygdala, hippocampus, ventral striatum, and cingulate cortex (ACC) /medial prefrontal cortex (mPFC). These brain areas, especially the ventral striatum, receive dopaminergic input from the ventral-tegmental area (VTA). Although there is a significant literature now showing that limbic brain tracks chronic pain intensity and predicts the risk of transition from sub-acute to chronic pain, the role of dopaminergic input to the limbic brain and the change thereof which occurs in chronic pain, is still not clear.

Given the role of dopamine in motivational control and the loss of motivation associated with chronic pain understanding how dopaminergic transmission is altered in the limbic brain of chronic pain patients is critical to the understanding of the pathophysiology of chronic pain. Therefore, the overall aim of this project is to use brain imaging to study how dopaminergic transmission through the oral administration of pro-dopaminergic medications carbidopa/levodopa (CD/LD) and methylphenidate will modulate the brain signature of chronic pain. Chronic pain subjects will be scanned at baseline (no drug administration) and three times after treatment with the two drugs or placebo. The protocol will follow a randomized double-blind approach.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

18 years old or older

Equal numbers of men and women, as well as racial and ethnic makeup representative of surrounding area

Able to speak, read, and understand English

In generally stable health

Disqualifiers

Significant other medical disease, such as unstable diabetes mellitus, congestive heart failure, coronary or peripheral vascular disease, chronic obstructive lung disease, or malignancy

History of traumatic brain injury (TBI)

Current misuse/dependence on substance(s), including alcohol, at the time of study enrollment

Major psychiatric disorder during the past 6 months

Trial design

Design model

Crossover

Treatments tested in this trial

  • Methylphenidate

    Drug

    0.5 mg/kg

  • carbidopa-levodopa

    Drug

    25 mg/100 mg

  • Placebo

    Drug

    oral pill

Treatment groups

10 Participants
are divided into 3 treatment groups
Group A: MethylphenidateActive comparator 1 intervention
Group B: Carbidopa/levodopa,Active comparator 1 intervention
Group C: PlaceboPlacebo comparator 1 intervention

Trial outcomes

Primary outcomes

1

mean change in amygdala volume

Amygdala volume will be measured using T1w MPRAGE structural images. The mean change in amygdala volume will be the volume of amygdala before administering the drug or placebo minus the volume of amygdala after administering the drug or placebo.

Time frame
baseline to 3 hours
2

mean change in hippocampus volume

Hippocampus volume will be measured using T1w MPRAGE structural images. The mean change in hippocampus volume will be the volume of hippocampus before administering the drug or placebo minus the volume of hippocampus after administering the drug or placebo.

Time frame
baseline to 3 hours
3

mean change in thalamus volume

Thalamus volume will be measured using T1w MPRAGE structural images. The mean change in thalamus volume will be the volume of thalamus before administering the drug or placebo minus the volume of thalamus after administering the drug or placebo.

Time frame
baseline to 3 hours
4

mean change in Nucleus accumbens volume

Nucleus accumbens volume will be measured using T1w MPRAGE structural images. The mean change in Nucleus accumbens volume will be the volume of Nucleus accumbens before administering the drug or placebo minus the volume of Nucleus accumbens after administering the drug or placebo.

Time frame
baseline to 3 hours

Secondary outcomes

1

Effort Expenditure for Reward Task (EEfRT)

This is a multi-trial task where subjects are given an opportunity on each trial to choose between two different task difficulty levels associated with varying levels of monetary reward. Each trial presents the subject with a choice between, a 'hard task' ((high cost/high reward (HC/HR) and an 'easy task' (low cost/low reward (LC/LR)) option, which require different amounts of speeded manual button pressing. For easy-task choices, subjects are eligible to win the same amount on each trial if they successfully complete the task. For hard-task choices, subjects are eligible to win higher amounts that vary per trial. Performance on EEfRT is modulated by mesolimbic dopamine transmission which is well known to be altered in chronic pain, and in MDD39. The responses are scored from 0 - 1 as proportions of high cost/high rewards tasks.

Time frame
baseline to 3 hours

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University of Rochester

Lead sponsor

Source ClinicalTrials.gov
Apply now