We have discovered and synthesized a series of indole-based derivatives as novel sigma-2(σ_(2))receptor ligands.Two ligands with high σ_(2) receptor affinity and subtype selectivity were then radiolabeled with F-18 ...We have discovered and synthesized a series of indole-based derivatives as novel sigma-2(σ_(2))receptor ligands.Two ligands with high σ_(2) receptor affinity and subtype selectivity were then radiolabeled with F-18 in good radiochemical yields and purities,and evaluated in rodents.In biodistribution studies in male ICR mice,radioligand[18F]9,or 1-(4-(5,6-dimethoxyisoindolin-2-yl)butyl)-4-(2-[18F]fluoroethoxy)-1H-indole,was found to display high brain uptake and high brain-to-blood ratio.Pretreatment of animals with the selective σ_(2) receptor ligand CM398 led to significant reductions in both brain uptake(29%-54%)and brain-to-blood ratio(60%-88%)of the radioligand in a dose-dependent manner,indicating high and saturable specific binding of[18F]9 to σ_(2) receptors in the brain.Further,ex vivo autoradiography in male ICR mice demonstrated regionally heterogeneous specific binding of[18F]9 in the brain that is consistent with the distribution pattern of σ_(2) receptors.Dynamic positron emission tomography imaging confirmed regionally distinct distribution and high levels of specific binding for[18F]9 in the rat brain,along with appropriate tissue kinetics.Taken together,results from our current study indicated the novel radioligand[18F]9 as the first highly specific and promising imaging agent for σ_(2) receptors in the brain.展开更多
基金supported by the National Natural Science Foundation of China(No.21876013)Beijing Natural Science Foundation(7212203,China)。
文摘We have discovered and synthesized a series of indole-based derivatives as novel sigma-2(σ_(2))receptor ligands.Two ligands with high σ_(2) receptor affinity and subtype selectivity were then radiolabeled with F-18 in good radiochemical yields and purities,and evaluated in rodents.In biodistribution studies in male ICR mice,radioligand[18F]9,or 1-(4-(5,6-dimethoxyisoindolin-2-yl)butyl)-4-(2-[18F]fluoroethoxy)-1H-indole,was found to display high brain uptake and high brain-to-blood ratio.Pretreatment of animals with the selective σ_(2) receptor ligand CM398 led to significant reductions in both brain uptake(29%-54%)and brain-to-blood ratio(60%-88%)of the radioligand in a dose-dependent manner,indicating high and saturable specific binding of[18F]9 to σ_(2) receptors in the brain.Further,ex vivo autoradiography in male ICR mice demonstrated regionally heterogeneous specific binding of[18F]9 in the brain that is consistent with the distribution pattern of σ_(2) receptors.Dynamic positron emission tomography imaging confirmed regionally distinct distribution and high levels of specific binding for[18F]9 in the rat brain,along with appropriate tissue kinetics.Taken together,results from our current study indicated the novel radioligand[18F]9 as the first highly specific and promising imaging agent for σ_(2) receptors in the brain.
