Postmortem human brain autoradiography

[¹¹C]TAZA, [¹¹C]PIB and [¹¹C]Dalene were used for autoradiographic studies. Human hippocampus sections (7 μm thick) were preincubated in buffer (40% EtOH) for 10 min. The brain sections were placed in a glass chamber and incubated with [¹¹C]TAZA, [¹¹C]PIB, and [¹¹C]Dalene (approximately 740 kBq/cc) in 40% EtOH at 37°C for 1 h. The slices were then washed with cold Millipore water, 70%–90%–70% EtOH, water for 2,1,1,1,1 min, respectively. Nonspecific binding was measured in the presence of 10 μM PIB. The brain sections were air-dried, exposed overnight on a phosphor film, and then placed on the Phosphor Autoradiographic Imaging System (Packard Instruments Co). Regions of interest (ROIs) were drawn on the slices and the extent of binding of ¹¹C-PIB was measured with DLU/mm² using the Opti-Quant acquisition and analysis program (Packard Instruments Co). Neighboring slices were immunostained with 4G8 antibody using modifications of reported methods (Braak et al., 2011). Slides were warmed to room temperature and washed in TBS (Tris-buffered saline, pH 7.5), followed by antigen ret-rival in 70% formic acid for 15 min. After endogenous peroxidase quenching, sections were stained with bio-tinylated anti-Aβ antibody 4G8 (Covance, Princeton, NJ) at 1:800 dilution followed by incubation according to manufacturer instructions (Vector Labs, Burlingame, CA). Peroxidase reaction was developed with 3,3′-diaminobenzidine reagent (Vector Labs, Burlingame, CA). Pictures were taken on Olympus BX61 microscope.