Article

Brain mu-opioid receptor binding: relationship to relapse to cocaine use after monitored abstinence

University of Pittsburgh School of Medicine Department of Radiology Pittsburgh PA USA
Psychopharmacology (Impact Factor: 3.99). 11/2008; 200(4):475-486. DOI: 10.1007/s00213-008-1225-5

ABSTRACT RationaleCocaine users have increased regional brain mu-opioid receptor (mOR) binding which correlates with cocaine craving. The relationship
of mOR binding to relapse is unknown.

ObjectiveTo evaluate regional brain mOR binding as a predictor of relapse to cocaine use is the objective of the study.

Materials and methodsFifteen nontreatment-seeking, adult cocaine users were housed on a closed research ward for 12weeks of monitored abstinence
and then followed for up to 1year after discharge. Regional brain mOR binding was measured after 1 and 12weeks using positron
emission tomography (PET) with [11C]carfentanil (a selective mOR agonist). Time to first cocaine use (lapse) and to first two consecutive days of cocaine use
(relapse) after discharge was based on self-report and urine toxicology.

ResultsA shorter interval before relapse was associated with increased mOR binding in frontal and temporal cortical regions at 1
and 12weeks of abstinence (Ps < 0.001) and with a lesser decrease in binding between 1 and 12weeks (Ps < 0.0008). There were significant positive correlations between mOR binding at 12weeks and percent days of cocaine use
during first month after relapse (Ps < 0.002). In multiple linear regression analysis, mOR binding contributed significantly to the prediction of time to relapse
(R
2 = 0.79, P < 0.001), even after accounting for clinical variables.

ConclusionsIncreased brain mOR binding in frontal and temporal cortical regions is a significant independent predictor of time to relapse
to cocaine use, suggesting an important role for the brain endogenous opioid system in cocaine addiction.

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Available from: David A Gorelick, Apr 19, 2015
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