Effects of Intramuscular (IM) Oxytocin on Pupil Diameter and Heart Rate Variability (HRV)

Effects of Intramuscular Oxytocin on Pupil Diameter and Heart Rate Variability

The goal of this study is to test the effects of oxytocin on heart rate variability and pupil diameter, both of which have subtle effects on the activity rate of the autonomic nervous system.

This protocol focuses on two measures of autonomic control to quantify central actions of oxytocin. First, the study team proposes to examine the influence of oxytocin on heart rate variability with focus on its effect on high frequency variability, most commonly ascribed to parasympathetic nervous system activity acting to brake sympathetic tone. Intranasal oxytocin has been demonstrated to have a large effect size on this measure which can be repeated at frequent intervals. As a secondary assessment of parasympathetic activity, the study team will measure low frequency fluctuation in pupil diameter, termed hippus, which also reflects parasympathetic nervous system activity. This outcome measure can be assessed in 3 seconds using equipment currently being used under Institutional Review Board (IRB) approved protocols.

Inclusion Criteria:

• Male or female > 18 and < 66 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.
• Previous eye surgery, eye medications, cataracts