potent P2X7 receptor antagonist, benzamide GSK1482160 was also radiolabeled with 11C to produce PET radioligand [11C]GSK1482160 (Ki = 2.63 nM, IC50 = 3 nM, hP2X7 and Kd = 1.15 ± 0.12 nM, hP2X7R).207-209 Evaluation of [11C]GSK1482160 in mouse model of LPS-induced neuroinflammation showed increased uptake of 3.6-fold compared with saline-treated mice in all studied organs (2.9- to 5.7-fold).208 In the EAE rat model of MS, [11C]GSK1482160 uptake was high in rat lumbar spinal cord and the highest uptake was measured at the EAE peak stage.209 Micro-PET studies of [11C]GSK1482160 in rhesus monkey has shown high tracer retention and a homogeneous brain distribution.209 All of these studies strongly correlated the [11C]GSK1482160 uptake with the P2X7 R overexpression on activated microglia and its participation in neuroinflammation.209 Another 11C PET radioligand of P2X7 R antagonist was developed by radiolabeling of the SMW139 (Ki = 32 nM, hP2X7R)210 and was evaluated in a humanized rat model to study the expression of P2X7R in striatum.210 Even though [11C]SMW139 did not detect overexpression of the P2X7 R in postmortem brain of patients with AD,210,211 this PET radioligand has entered clinical evaluation in patients with MS and is currently the first in human to study neuroinflammation in
