Abstract # 4223 Poster # 142:

Scheduled for Friday, June 22, 2012 07:00 PM-09:00 PM: Session 22 (Gardenia) Poster Presentation


IN VIVO AND IN VITRO METHODS FOR LOCALIZING THE OXYTOCIN RECEPTOR IN PRIMATE TISSUE

S. M. Freeman1,2,4, A. L. Smith1,2,3, M. M. Goodman1,3 and L. J. Young1,2
1Emory University, Yerkes National Primate Research Center, Neuroscience Building, 954 Gatewood Rd. NE, Atlanta, GA 30329, USA, 2Center for Translational Social Neuroscience, 3Department of Radiology, 4Neuroscience Graduate Program
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     The prosocial behavioral effects of oxytocin (OT) have been studied in various animal species for decades, including recent progress examining OT and human social behavior. Despite this new research using OT in humans, the neuroanatomical distribution of the oxytocin receptor (OTR) in the human (and non-human primate) brain has not been elucidated. This is due to a lack of reliable OTR antibodies and to a non-selective radioligand for receptor autoradiography, which exhibits a mixed affinity in primates for OTR and vasopressin 1a receptor (V1aR). As the study of OT in primates progresses, it is critical to determine where OTR is expressed in primate brain. To achieve this goal, we have been working on two detection methods: development of an OTR PET ligand for in vivo neuroimaging and a pharmacologically informed modification for receptor autoradiography in post-mortem brain sections. We report here the biological evaluation of a novel candidate OTR PET ligand as well as brain scans performed on rhesus and cynomolgus macaques. We also report the pharmacological characterization of the aforementioned OTR radioligand for competitive binding in primate tissue. This method involves co-incubating tissue with a V1aR ligand to block the radioligand’s non-specific binding in order to reveal the specific OTR distribution. With novel in vivo and ex vivo detection methods, our work lays the foundation for future work in the primate oxytocin system.