Effects of Anticipation of Pain Relief on Brain Mechanisms
This study will use brain imaging technology to examine chemical systems in the brain that suppress pain and stress when an individual has an expectation of pain relief.
|Study Design:||Allocation: Non-Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Single Blind
Primary Purpose: Diagnostic
|Official Title:||Neurochemical Mediation of Placebo Responses in Humans|
- Placebo-induced activation of brain opioid neurotransmission
|Study Start Date:||September 2003|
|Study Completion Date:||June 2008|
|Primary Completion Date:||February 2008 (Final data collection date for primary outcome measure)|
Evidence suggests that the expectation of pain relief, even if a person receives only a placebo, can provide actual therapeutic benefits. The µ-opioid receptor system, located in the brain, is activated during anticipation of pain relief; this activation suppresses stress and pain responses. This study will use brain imaging technology to examine the effects of a placebo intervention on µ-opioid neurotransmitters. Examination of the factors that regulate these placebo-activated neurotransmitter responses will clarify the overall neurobiology underlying variations in the responses to placebos, as well as pain and other stressful conditions, ultimately leading to the optimization of medical and psychological interventions.
This study will last several hours during one study visit. Participants will receive both a painful and a painless injection while undergoing positron emission tomography (PET) brain imaging. The painful injection will consist of small amounts of hypertoninc saline (concentrated saline that causes cell shrinkage) in the jaw muscle over a 20-minute period. Several minutes after participants receive hypertonic saline, they will receive an injection with isotonic saline not associated with pain in the opposite jaw muscle. After participants receive the injections, they will either be told or not be told about a pain relief intervention. PET imaging will continue as participants either anticipate or do not anticipate pain relief. Participants will be asked about their pain levels repeatedly throughout the study; their responses will be entered into a computer-controlled system which will modulate rates of saline infusion.
|United States, Michigan|
|University of Michigan Medical Center|
|Ann Arbor, Michigan, United States, 48109|
|Principal Investigator:||Jon-Kar Zubieta, MD, PhD||University of Michigan|