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.