Briefly, ultrathin sections (80 nm thick) from Lowicryl-embedded blocks of hippocampus were collected on single slot pioloform-coated nickel grids and incubated on drops of a blocking solution consisting of 2% human serum albumin in 0.05 M TBS and 0.03% (v/v) Triton X-100. The grids were incubated with GIRK1, GIRK2 or GIRK3 antibodies [10 μg/mL in 0.05 M TBS and 0.03% (v/v) Triton X-100 with 2% (w/v) human serum albumin] at 28 °C overnight. The grids were incubated on drops of goat anti-guinea pig IgG or goat anti-rabbit IgG conjugated to 10 nm colloidal gold particles (Nanoprobes) in 2% (w/v) human serum albumin and 0.5% (w/v) polyethylene glycol in 0.05 M TBS and 0.03% (v/v) Triton X-100. The grids were then washed in TBS and counterstained for electron microscopy with saturated aqueous uranyl acetate followed by lead citrate.
