Effects of Anticipation of Pain Relief on Brain Mechanisms

Sponsor

University of Michigan (Other)

Overall Status

Completed

CT.gov ID

NCT00200876

Collaborator

National Center for Complementary and Integrative Health (NCCIH) (NIH)

Enrollment

Location

Arms

Duration (Months)

1.1

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Pain	Procedure: Hypertonic saline Procedure: Isotonic saline	N/A

Detailed Description

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.

Study Design

Study Type:

Interventional

Actual Enrollment :

60 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Intervention Model Description:

Hypertonic saline is a challenge to activate endogenous opioid systems as assessed with positron emission tomography. There is no treatment involved. Isotonic saline is the control.Hypertonic saline is a challenge to activate endogenous opioid systems as assessed with positron emission tomography. There is no treatment involved. Isotonic saline is the control.

Masking:

Triple (Participant, Investigator, Outcomes Assessor)

Primary Purpose:

Diagnostic

Official Title:

Neurochemical Mediation of Placebo Responses in Humans

Study Start Date :

Sep 1, 2003

Actual Primary Completion Date :

Feb 1, 2008

Actual Study Completion Date :

Jun 1, 2008

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: pain challenge	Procedure: Hypertonic saline To elicit pain Procedure: Isotonic saline Non-painful control
Sham Comparator: non-painful control	Procedure: Hypertonic saline To elicit pain Procedure: Isotonic saline Non-painful control

Arm

Intervention/Treatment

Active Comparator: pain challenge

Procedure: Hypertonic saline

To elicit pain

Procedure: Isotonic saline

Non-painful control

Sham Comparator: non-painful control

Procedure: Hypertonic saline

To elicit pain

Procedure: Isotonic saline

Non-painful control

Outcome Measures

Primary Outcome Measures

Placebo-induced activation of brain opioid neurotransmission [90 min]

Eligibility Criteria

Criteria

Ages Eligible for Study:

20 Years to 30 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Willing and able to comply with all study requirements

Exclusion Criteria:

Presence of pain at study entry
Personal or first-degree (e.g., mother, father, sister, brother) family history of neurologic or psychiatric disorders
History of substance abuse or dependence
Left-handed or ambidextrous
Positive urine toxicology screen
Acute or uncorrected medical illness that may interfere with the study
Unable to tolerate brain scanning procedures
Current treatment with antipsychotics, mood stabilizers, isoniazid (a drug for tuberculosis [TB]), glucocorticoids/mineralocorticoids, psychostimulant appetite suppressants, or centrally active antihypertensive drugs
Treatment with hormones, antidepressants, or opioids within 6 months prior to study entry
Treatment with sedative hypnotic medications or over-the-counter sleeping aids within 1 month prior to study entry
Diagnosis of depression
Competitive exercise, or exercise exceeding 1 hour each day
Regular smoking within 5 years prior to study entry