Abstract/summary PET imaging can be potentially used to quantify biochemical processes underlying pain and drug addiction mechanisms at molecular level by detecting the expression level of α2δ-1 receptor. Due to the low CNS permeability of the first generation of α2δ-1 PET tracers (see preliminary data), the lesion cannot be detected by PET imaging. This proposal is focused on the development of the next generation of α2δ-1 PET tracers, which are expected to show high CNS uptake and be more suitable for neuroimaging. In order to achieve the high CNS permeability, two categories of tracers, namely trans-4-[18F]fluorogabapentin prodrug (Aim 1A) and novel pyrazolopyridazine α2δ-1 radiotracer (Aim 1B), are proposed. The proposed PET tracers will be first screened in heathy mice. The promising candidates with good CNS permeability and pharmacokinetic properties will be fully characterized in health rats, and healthy non-human primates (NHPs) (Aim 2). We will also explore the applications of newly designed tracers in animal models of pain and animal models of drug addiction such as spinal nerve ligation (SNL) rats and ethanol dependence mice, respectively (Aim 3). We hypothesize these tracers will show moderate to high CNS permeability and enable the detection of PET signal changes that correlate with the neuropathic pain and drug addiction progression. The proposed project will provide necessary data for a future clinical study.

Narrative PET neuroimaging of α2δ-1 receptor can provide a measure of biochemical processes underlying pain and drug addiction at the molecular level. However, due to the low CNS permeability of current α2δ-1 PET tracers, the neuroimaging of α2δ-1 receptor has not been achieved. In order to address these limitations, next generation of α2δ-1 PET tracers is proposed.