Effects of Intramuscular Oxytocin on Sensory Function in Healthy Volunteers With Ultraviolet Burn Injury to the Skin

Effects of Intramuscular Oxytocin on Sensory Function in Healthy Volunteers With Ultraviolet Burn Injury to the Skin

This study proposes to evaluate the effects that a dose of oxytocin given by intramuscular (IM) injection (into the muscle) will have on an area of skin that has been exposed to ultraviolet (UV) light. The area of skin exposed to UV light will have a mild sun burn feeling.

Sensory testing will be performed on the area of UV burn. The area will be evaluated for sensitivity in 3 methods: touch, vibratory

This protocol aims to provide an estimate of effect size of intramuscular oxytocin on a test of Aβ and of Aδ fiber sensitivity in injured skin following ultraviolet B (UVB) burned skin.

For the primary goal - to examine the effects of oxytocin peripheral nerves after tissue injury - the investigators chose the controlled ultraviolet sunburn model.

The investigators propose a randomized, blinded, cross over design with treatment with oxytocin one day and placebo on another. Following baseline measures on each of the two study days, participants will receive an intramuscular injection of oxytocin (Pitocin®) in its indicated dose of 10 IU (17 μg) or an equivalent volume of saline.

In order to determine the highest frequency that Aβ nerve fibers can respond to, the investigators will use a device that produces an oscillatory / vibratory stimulus which can be used on the hand.

Pain threshold to punctate stimulation within the area of irradiation will be determined using calibrated von Frey filaments and an up-down sequential method which efficiently estimates median thresholds.

Thermal heat testing will also be performed by the surface of the skin of the forearm or leg is heated to 45°C using a computer controlled thermode for a period of 5 minutes.

Inclusion Criteria:

• Male or female > 18 and < 60 years of age,
• Body Mass Index (BMI) <40
• Generally in good health as determined by the Principal Investigator based on prior medical history
• Normal blood pressure and resting heart rate without medication

Exclusion Criteria:

• Hypersensitivity, allergy, or significant reaction to any ingredient of Pitocin®
• Any disease, diagnosis, or condition (medical or surgical) that, in the opinion of the Principal Investigator, would place the subject at increased risk
• Women who are pregnant (positive result for serum pregnancy test at screening visit), women who are currently nursing or lactating, women that have been pregnant within 2 years.
• Neuropathy, chronic pain, diabetes mellitus, or taking benzodiazepines or pain medications on a daily basis.