Fig. 6.

Representative [¹⁸F]-Flortaucipir (left), [¹⁸F]-MK-6240 (center), and [¹⁸F]-PI-2620 phosphor screen autoradiography experiments in adjacent slices containing temporal cortex from an AD case using competing concentrations of 1 μM clorgyline or harmine (MAO-A inhibitors) and deprenyl (MAO-B inhibitor). [¹⁸F]-Flortaucipir, [¹⁸F]-MK-6240, and [¹⁸F]-PI-2620 binding signals were only weakly displaced with 1 μM deprenyl (a selective MAO-B inhibitor). When a competing concentration of 1 μM clorgyline (a selective MAO-A inhibitor) was added to the blocking solution, no [¹⁸F]-Flortaucipir, [¹⁸F]-MK-6240 or [¹⁸F]-PI-2620 autoradiographic signal displacement could be detected. A more robust displacement of the three tracer signals was observed when a competing concentration of 1 μM harmine (dual inhibitor of DYRK1A and MAO-A) was added to the blocking solution. Scale bar = 1 cm