Completed
PHASE2
INTERVENTIONAL
NCT05326776
Peripheral Oxytocin and Touch
View on ClinicalTrials.gov
Updated Dec 15, 2025
Brief Summary
Research shows that slow gentle skin stroking can activate special sensory nerves in the skin that elicit relaxing effects on the body and mind, similar to the effects of the hormone oxytocin. Studies also suggest that gentle stroking may even release oxytocin in the skin. However, we do not know what oxytocin does in the skin and how it affects nerves that send pleasant touch or pain signals to the brain. The proposed study will determine how individuals perceive gentle stroking and experimental pain before and after a skin injection of oxytocin compared to a placebo injection.
Interventions
Name:
Pitocin
Type:
DRUG
Description:
At each session, 4mcg/2ml oxytocin or 2ml isotonic saline (0.9% sodium chloride; placebo control) will be injected into the middle of the dorsal forearm. Sessions will be separated by at least 48 hours to ensure drug clearance.
Primary Outcomes
Measure:
Change in Mean Pleasantness Rating of Gentle Brushing
TimeFrame:
Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)
Description:
Touch pleasant/unpleasantness ratings will be assessed in response to slow gentle brushing using a "Pleasantness/Unpleasantness" Visual Analog Scale with anchors of "Extremely unpleasant" (coded -100) to "Neutral" to "Extremely pleasant (coded 100)." Change in mean rating of slow brushing will be compared between the oxytocin and placebo sessions. Higher values indicate increased pleasantness (better outcome).
Measure:
Change in Mechanical Threshold
TimeFrame:
Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)
Description:
"Mechanical threshold" task. Change in first reported percept of sharpness from application of a standard set of weighted pinprick stimuli (minimum 8mN; maximum 512 mN) will be compared between the oxytocin and placebo sessions. An increased threshold indicates reduced sensitivity to mechanical pain.
Measure:
Change in Temporal Summation of Pinprick Stimuli
TimeFrame:
Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)
Description:
Temporal summation will be tested using a standard 256 milliNewtons (mN) pinprick stimulus applied for 10 repetitions. The participant will provide pain ratings for a single pinprick and for the 10 repetitions, using a Visual Analog Scale rating scale with anchors "No pain" to "Most intense pain imaginable." This procedure will be repeated 5 times and the mean pain rating for the repeated pinprick will be divided by the mean rating of the single pinprick to obtain the standard temporal summation ratio. Change in ratio will be compared between the oxytocin and placebo sessions.
Trial Information
NCT ID
NCT05326776
Status
Completed
Study Type
INTERVENTIONAL
Phases
PHASE2
Sponsor
University of California, San Diego
Last Updated
December 15, 2025