Predictors of Opioid Analgesic Responses and Common Endogenous Opioid Mechanisms

This study will focus on differences between both healthy people and people with lower back pain in how they respond to brief laboratory pain tasks while taking morphine, taking a substance that blocks the natural opioid-based pain systems in the body (naloxone), and while taking a placebo. You will receive compensation for your time and travel.

You may be eligible to participate in this study if you:

• Have had low back pain for at least six months or are healthy
• Are 18 to 55 years of age

You will be excluded from this study if you:

• Have cancer or rheumatoid arthritis
• Have other severe medical or psychiatric disorders

This is a partial list of eligibility requirements. To inquire about your eligibility, please call the contact number provided. If you wish to inquire via e-mail, please include the title of the study in your message.