Autoradiographic mapping of synaptic vesicle glycoprotein 2A in non-human primate and human brain.

Synaptic vesicle glycoprotein 2A (SV2A) has been previously characterized as an imaging biomarker for assessment of synaptic density in positron emission tomography (PET) studies of patients with neurological conditions. To provide detailed maps of the brain localization of SV2A autoradiography studies were carried out using the SV2A radioligand [ C]UCB-J and whole hemisphere sections of non-human primate (NHP) and human brain. Binding of [ C]UCB-J was observed in all evaluated grey matter structures of the primate brain, with highest density in the caudate nucleus and cortex and lowest density in pons and globus pallidus. The density of [ C]UCB-J binding sites in human brain showed a good correlation with that in NHP brain. Binding of [ C]UCB-J in the white matter was very low relative to that in grey matter containing structures and was only inhibited to a minor extent by co-incubation with a saturating concentration of unlabelled UCB-J. The high-resolution images obtained in the present study may aid the interpretation of data acquired in human subjects examined using [ C]UCB-J in PET studies. In addition, observation of low binding for [ C]UCB-J in white matter (centrum semiovale) supports that this structure can be used as a reference region for quantitative analysis of [ C]UCB-J PET data.