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RM1 Project 1 - tAN Naloxone

Evaluating the Specific Role of Endogenous Opioids as the Mechanism Underlying tAN-based Analgesia in Healthy Individuals

Who can join

Ages 18 to 65 · All sexes · Healthy volunteers welcome

Inclusion Criteria:

* Age 18-65
* Have the capacity and ability to provide one's own consent and sign the informed consent document

Exclusion Criteria:

* Contraindicated for MRI.
* Any current or recent untreated medical, neurological, or psychiatric conditions
* Metal implant devices in the head, heart or neck.
* History of brain surgery.
* History of myocardial infarction or arrhythmia, bradycardia.
* Personal or family history of seizure or epilepsy or personal use of medications that substantially reduce seizure threshold (e.g., olanzapine, chlorpromazine, lithium).
* Personal history of head injury, concussion, or self-report of moderate to severe traumatic brain injury.
* Individuals suffering from frequent/severe headaches.
* Individuals with a reported history of psychosis or mania, or individuals who are actively manic or psychotic.
* Regular or recent pain medication use
* Moderate to severe alcohol or substance use disorder.
* Psychotropic or cardiac medicines that may interact with naloxone
* Positive urine drug screen for opiate use
* Females who are pregnant or lactating

About the study

This two-visit, randomized, double-blind, sham-controlled trial, uses a novel naloxone blockade model in 136 individuals to determine whether the analgesic effects of a 30-minute transcutaneous auricular neurostimulation (tAN) intervention are mediated through a release of endogenous opioids. Analgesic effects of four various stimulation interventions will be measured (auricular vagus, auricular trigeminal, combination, or sham) while varying the type of intravenous (IV) infusion (either naloxone or saline) a participant is administered to determine whether the analgesic effects are mitigated by pharmacological opioid receptor blockade.

What is being tested

• Naloxone (drug)
• Saline (drug)

Sponsor: Medical University of South Carolina · Participants: 136 · Started: Mar 22, 2023

Contact the study team

• Bashar Badran, PhD · Phone: 8437926076

Official record on ClinicalTrials.gov — NCT05490134

Locations in the U.S.

From ClinicalTrials.gov, data retrieved Sep 30, 2026. Each study sets its own eligibility; the study team decides who can join.