[3H]M503-1619

[3H]M503-1619 is a tritium-labeled radioligand developed for the detection and characterization of alpha-synuclein (α-syn) aggregates, which are pathological hallmarks of synucleinopathies such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Developed by researchers at the University of Pennsylvania, the compound targets a specific binding site designated as "Site 9" on α-syn fibrils. In vitro autoradiography studies using human post-mortem brain tissue have demonstrated that [3H]M503-1619 preferentially binds to α-syn inclusions in PD and DLB samples but shows negligible binding in multiple system atrophy (MSA) tissue. This selectivity suggests that the ligand can distinguish between different conformational strains of α-syn, making it a potentially powerful tool for differential diagnosis and the study of disease-specific protein folding in neurodegenerative disorders.