Peripheral Oxytocin and Touch

Phase 2

Completed

Conditions: Healthy Adults

Interventions: Drug: Pitocin

Registration Number: NCT05326776

Lead Sponsor: University of California, San Diego

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.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 20

Inclusion Criteria

Between the ages of 18 and 65 years old
Fluent in English
Healthy

Exclusion Criteria

Sensory or motor nerve deficit
Acute or chronic pain
Major medical conditions such as kidney, liver, cardiovascular (hypertension, preexisting cardiac arrhythmia), autonomic, pulmonary, or neurological problems (e.g., seizure disorder) or a chronic systemic disease (e.g., diabetes).
Any disease, diagnosis, or condition (medical or surgical) that, in the opinion of the Principal Investigator, would place the subject at increased risk (active gynecologic disease in which increased tone would be detrimental e.g., uterine fibroids with ongoing bleeding), compromise the subject's compliance with study procedures, or compromise the quality of the data
Unstable psychiatric conditions
Needle phobia or history of fainting
Current use of opiate medication(s)
Hypersensitivity, allergy, or significant reaction to any ingredient of Pitocin®
Currently pregnant or pregnant within the last two years
Currently nursing or lactating
Current or history of ventricular tachycardia, atrial fibrillation or prolonged QT interval
Past or current history of hyponatremia or at risk for hyponatremia
Current use of thiazide diuretics, loop diuretics, combination diuretics, lithium, carbamazepine, enalapril, Ramipril, celecoxib, temazepam, gliclazide, glimepiride, glibenclamide, glipizide, omeprazole, pantoprazole, desmopressin, selective serotonin reuptake inhibitors, monoamine oxidase inhibitora, or the recreational drug ecstasy
Latex allergy

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Order 1	Pitocin	Participants will receive 4mcg/2ml oxytocin during Session 1 and 2ml isotonic saline during Session 2, injected into the forearm.
Order 2	Pitocin	Participants will receive 2ml isotonic saline during Session 1 and 4mcg/2ml oxytocin during Session 2, injected into the forearm.

Primary Outcome Measures

Name	Time	Method
Change in Mean Pleasantness Rating of Gentle Brushing	Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)	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).
Change in Mechanical Threshold	Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)	"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.
Change in Temporal Summation of Pinprick Stimuli	Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)	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.

Secondary Outcome Measures

Name	Time	Method
Pressure Pain Threshold	Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)	Pressure pain threshold will be tested using a pressure algometer placed over the dorsal forearm muscles, and pressure will be increased until pain is reported. When pain is reported, the pressure level (in pounds of force) is recorded as the outcome measure.
Heat Pain Threshold	Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)	Heat pain threshold (HPT) will be tested using a high-quality thermode. To establish HPT, the thermode will be placed on the arm at a baseline temperature of 32 Celsius and will be increased until the stimulus is reported as painful by the participant. The mean of three trials will be taken as the HPT.
Heat Pain Ratings	Baseline and time of intervention at both the Oxytocin Session and Placebo Session (Sessions spaced a minimum of 3 days apart)	Three 10s trials of the individually calibrated heat stimulus rated 70/100 will be rated using using a "Pain Intensity" Visual Analog Scale rating scale with anchors "No pain" (coded -100) to "Most intense pain imaginable (coded 100)." Higher scores indicate more intense pain (worse outcome).