ESP2Mechanisms of Sleep Disruption Hyperalgesia

This research is being conducted in order to evaluate the effects of disrupted sleep patterns on mood, inflammation, the perception of pain, and pain relief. This study will help researchers understand the relationship between sleep and pain, and how sleep disturbance might influence chronic pain conditions. Healthy participants will undergo baseline sleep and sleep disruption conditions. Following undisturbed sleep and sleep disruption conditions, sensitivity to pain and analgesic response (via morphine or placebo administration) will be assessed using a heat-capsaicin pain model. This study will be conducted in 2 major parts-3 screening visits (2 outpatient and 1 inpatient) and 2 experimental inpatient visits. Part 1 of the study will involve a 1-week screening period. This will involve two separate screening visits lasting about 2 hours each. At Screening Visit 1, participants will complete questionnaires, an interview, and undergo toxicology screening. At Screening Visit 2, participants will complete questionnaires, undergo a physical exam, and be familiarized with pain testing procedures. At Screening Visit 3, participants will undergo an inpatient sleep study. Part 2 will involve two different inpatient admissions. The two admissions will be separated by at least two weeks. During each of the admissions, participants' sleep will be studied at night. The first admission will begin immediately following the overnight sleep study in Screening Visit 3. One of the admissions will be for one night and the other admission will be for three nights. For the one night admission, participants will sleep undisturbed for an 8-hour period. For the three night admission, participants will undergo sleep disruption for two nights in a row. On the third night, participants will be allowed to sleep undisturbed for 8 hours for recovery. During both inpatient admissions, pain testing procedures will be completed that will last approximately 5 hours during the day. During testing, small amounts of blood will be drawn for analysis. Participants will be randomly assigned to two groups. Group A will be given a standard dose of morphine during pain testing. Group B will be given a placebo during pain testing.