Brain Effects of Opiate Agonist and Antagonist

Study Overview
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Brief Summary
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This study will look at the short-term effect of morphine on brain response to food.

Detailed Description
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Chronic low back pain patients and healthy controls will be recruited for this study. Participants' brain will be scanned at baseline and then again on a different day after the administration of an oral dose of 30 mg morphine in an open label design. Participants will receive morphine 60 minutes prior to the start of the second scanning session. The brain scans will include structural scans, functional scans at rest and functional scans during the ingestion of a highly caloric drink.

Official Title
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Brain Effects of Opiate Agonist and Antagonist

Conditions
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Chronic Low-back Pain

Intervention / Treatment
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* Drug: Morphine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy participants Patients in pain: suffering from persistent pain more days than not, 3/10 in intensity on a numerical rating scale, for at least 6 weeks or more. Exclusion Criteria: Any DSM diagnosis diabetes food allergies lactose intolerance participants seeking to quit smoking or to lose weight participants on any psychotropic medication including opiate based analgesics (e.g. oxycodone, methadone, suboxone) pregnant or nursing women pacemaker or other implanted electrical devices Participants with a past history of head trauma or seizures Any past history of illegal drug or alcohol misuse Participants who cannot undergo an MRI scan.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: All Participants<br>People with low back pain who were given and oral dose of 30 mg morphine. | Drug: Morphine<br>* 30 mg oral tablet<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Change in Subcortical Brain Structure Volume | Magnetic Resonance Imaging (MRI) scanning was performed to collect brain volume measurements in cc. There were 4 different areas of the brain that were analyzed. | baseline to 1 hour | 
| Change in Brain Response to Highly Caloric Drink | Participants received a highly caloric drink and a tasteless solution during a functional MRI scanning session. A general linear model was used to generate the magnitude of the fit for each type of stimuli and differences between the fits were calculated. A within subject analysis approach was used to calculate the effect of an acute dose of morphine on brain response to the highly caloric drink. Participants contributed beta values that were averaged across subjects and based on the average and standard deviation, the software, FSL, calculated Z = 4.38. This value indicates 4.38 standard deviations away from the mean in a distribution with a mean of zero and standard deviation of 1, which is the definition of the Gaussian curve (Z-distribution). It is scientifically not valid to say there is a higher or lower brain response. A Z-score = 0 means no change from baseline in brain response; a Z-score different from zero indicates a change from baseline after the ingestion of morphine. | baseline to 1 hour | 
| Mean Change in Resting Brain Activity in the Nucleus Accumbens | Participants were scanned at rest during a functional MRI session. The resting brain activity was measured as the Power spectral density slow-4 frequency band. Data collected in the frequency range 0 and 0.5 Hertz was analyzed. We examined the power spectral density in the range of 0.027 to 0.073 Hertz. The mean change is expressed as arbitrary units after a Fourier transformation of the data which cancels out the units. The mean change ranges from 0 to 175. The higher the number the more energy within that frequency band. | baseline to 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Change in Back Pain Intensity | Pain was rated using a visual analog scale ranging from 0-100 with 100 indicating the worst imaginable pain ever. | baseline to 1 hour |