Not yet taking people in FranceNo phase

Studies brain opioid and noradrenaline systems in Parkinson pain

Compares brain receptors in Parkinson patients with and without central pain using scans.

Key facts

Who runs it: Hospices Civils de Lyon
Where: Bron, Clermont-Ferrand, and Toulouse, FranceSee the 3 sites
Trial code: NCT07127146
Registry title: Opioidergic and Noradrenergic Systems in Central Parkisonian Pain
Status: Not yet recruiting
People taking part: 55 people, planned
Started: 1 Oct 2025
Planned end: 1 Oct 2025
Type of study: Interventional, 3 groups
Treatments tested: PET-MRI exam with administration of [11C]Carfentanil
PET-MRI exam with administration of [11C]Yohimbine
Record updated: 17 August 2025

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults aged 30 to 75 with Parkinson's disease, with or without chronic central pain, to study how the opioid and noradrenergic systems work in the brain using PET-MRI scans.

Age: 30 to 75 years
Sex: All sexes can join.
Disease stage: Parkinson's disease. One group has central pain for more than 3 months with pain of at least 4 on the pain scale (VAS) in the last month. Other groups have no chronic pain and pain below 3 on the scale.
Earlier treatment: Dopamine treatment must be stable, with a stable dose for at least 4 weeks before the start. Opioid medicines must be stopped the week before the scan. Pain medicines such as paracetamol or anti-inflammatory drugs must be stable for at least 4 weeks and must not affect the noradrenergic system.

Main reasons for not taking part

Atypical Parkinson's disease
Disabling dyskinesia or severe tremor
Cannot have a brain MRI or PET scan (for example pacemaker, metal in the body, claustrophobia)
Memory or thinking problems (MoCA score below 24) or severe depression (BDI above 29)
Pregnant or breastfeeding women

The registry criteria, word for word

Show all 28 criteriaShow less

Who can take part

Diagnosis of Parkinson's disease based on MDS-UPDRS criteria (Group 1 and 2)
Dopaminergic therapy stable with stable dose for at least 4 weeks prior to J0
Affiliate to a social security or similar system
Having given written consent to participate in the study, free and informed
Having chronic pain more than 3 month (Group 1)
Without chronic pain (Groupe 2 and 3)
Having central pain using specific algorithm (Marques et al., 2019)
Having pain intensity at least 4 on VAS (Visual Analogue Scale) during the last month (Group 1)
Having pain intensity lower than 3 on VAS (Visual Analogue Scale) during the last month (Group 2 and 3)

Who cannot take part

unable to stop the opioid treatment the week before the imaging exam ( e.g., Antarène codéine, Claradol codéine, Codoliprane, Dafalgan codéine, Euphon, Klipal, Lindilane, Néo-codion, Paderyl, Prontalgine, Pulmoserum, Tussipax ; Opium : Izalgi, Lamaline, Colchimax, Dropizal ; Morphine : Actiskenan, Moscontin, Oramorph, Sevredol, Skenan ; Buprénorphine : Bupensan, Buvidal, Orobupre, Sixmo, Suboxone, Subutex, Temgesic, Zubsolv ; Dihydrocodéine : Dicodin ; Hydromorphone : Sophidone ; Nalbuphine : Nalpain ; Fentanyl : Abstral, Actiq, Breakyl, Durogesic, Effentora, Instanyl, Matrifen, Pecfent, Recivit ; Méthadone : Methadone AP-HP, Zorvon ; Oxycodone : Oxsynia, Oxycontin, Oxynorm, Oxynormoro ; Tramadol : Biodalgic, Contramal, Ixprim, Monoalgic, Monocrixo, Orozamudol, Skudexum, Topalgic, Zaldiar, Zamudol, Zumalgic)
Treated with level 1 analgesics (NSAIDs, acetaminophen) or coanalgesics (antidepressants, antiepileptics) unless treatment has been stable for at least 4 weeks prior to the study and does not interfere with the noradrenergic system (list above)
Having used recreational drugs interfering with the opioid and noradrenergic systems (cannabis, CBD, opiates, MDMA, ecstasy) in the last 3 months or chronic use
Having atypical Parkinson's disease (Group 1 and 2)
Parkinson's disease with disabling dyskinesia and/or severe tremor (Group 1 and 2)
History of head trauma with loss of consciousness lasting more than 30 minutes
Under psychiatric care
Any contraindications to having a brain MRI or PET scan (e.g., pacemaker, metal foreign body, claustrophobia, deep brain stimulation or apomorphin pump unable to be turn off)
Not agreeing to be informed in the event of incidental discovery of an abnormality on MRI or during neuropsychological assessment
Presence of cognitive dysfunction (defined as MoCA score < 24)
Severe depression (BDI > 29)
unable to stop any treatment
Presenting or having presented a dependence on any addictive substance according to DSM-IV-TR criteria, with the exception of tobacco
Pregnant women, women in labor or nursing mothers
Persons deprived of their liberty by judicial or administrative decision
Admitted to a health or social institution for purposes other than research
Under legal protection (guardianship, curatorship)
Participant in another interventional study with an exclusion period still in progress at pre-inclusion
Having exceeded the annual amount of compensation authorized for participation in research protocols

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

Are you between 30 and 75 years old?

Where in France

Hôpital Neurologique Pierre WertheimerBron, FranceContact: Mathilde Millot-Troesch, CRANo longer taking part
CHU de Clermont-Ferrand Hôpital Gabriel MontpiedClermont-Ferrand, FranceContact: Anna MARQUES, PHDNo longer taking part
CHU de Toulouse - Hôpital PurpanToulouse, FranceContact: Christine Brefel-Courbon, MDNo longer taking part

About the trial

What the trial wants to find out

The goal of this study is to evaluate the differences in functional physiopathology of the opioid and noradrenergic systems between Parkinson's patients with central pain and Parkinson's patients without central pain. Using PET-MRI data, investigators aim to observe opioids receptors availability using [11C]Carfentanil (µ opioid receptor agonist) and altered α2-AR density with [11C]Yohimbine (adrenergic α2 receptor antagonist).

The 3 groups in the trial

PD-P (Parkinson's patient with pain)Treatment being tested
Parkinson's patients suffering from chronic and central pain and with a VAS score of at least 4 points. They will perform 2 different PET MRI with radiotracer , one using \[11C\]Carfentanil and the other one using \[11C\]Yohimbine
Treatment: PET-MRI exam with administration of [11C]Carfentanil and PET-MRI exam with administration of [11C]Yohimbine
PD-NP (Parkinson's patient with no pain)Treatment being tested
Parkinson's patients without chronic and central pain and with a VASscore below 3 points They will perform 2 different PET MRI with radiotracer , one using \[11C\]Carfentanil and the other one using \[11C\]Yohimbine
Treatment: PET-MRI exam with administration of [11C]Carfentanil and PET-MRI exam with administration of [11C]Yohimbine
Healthy volunteersTreatment being tested
Healthy volunteers without chronic pain and with a VAS score below 3 points They will perform a PET MRI with the \[11C\]Carfentanil radiotracer
Treatment: PET-MRI exam with administration of [11C]Carfentanil