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[11C]Carfentanil Binds Preferentially to µ-Opioid Receptor Subtype 1 Compared to Subtype 2.
- Source :
-
Molecular Imaging . Oct2015, Vol. 14, p476-483. 8p. - Publication Year :
- 2015
-
Abstract
- The positron emission tomography (PET) ligand [11C]carfentanil is a selective agonist for μ-opioid receptors and has been used for studying μ-opioid receptors in the human brain. However, it is unknown if [11C]carfentanil binding differentiates between subtype receptors μ1 and μ2. In this study, we investigated whether μ1 and μ2 can be studied separately through receptor subtype–selective inhibition of [11C]carfentanil by pharmacologic intervention. [11C]Carfentanil binding characteristics on rat brain sections were assessed either alone or in the presence of the μ-receptor inhibitor cyprodime or the μ1-specific inhibitor naloxonazine. [11C]Carfentanil binding in the living rat brain was similarly studied by small animal PET/computed tomography during baseline conditions or following displacement by cyprodime or naloxonazine. Autoradiography binding studies on rat brain sections demonstrated that [11C]carfentanil has higher affinity and binding potential for μ1 than for μ2. [11C]Carfentanil binding to μ2 in vivo could not be detected following specific blocking of μ1, as predicted from the low binding potential for μ2 as measured in vitro. [11C]Carfentanil binding is preferential for μ1 compared to μ2 in vitro and in vivo. Clinical studies employing [11C]carfentanil are therefore likely biased to measure μ1 rather than μ2. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15353508
- Volume :
- 14
- Database :
- Academic Search Index
- Journal :
- Molecular Imaging
- Publication Type :
- Academic Journal
- Accession number :
- 110262573
- Full Text :
- https://doi.org/10.2310/7290.2015.00019