Slice preparation of rat dorsal root ganglion. A) Overview of a 150 μm slice of a DRG embedded in agar at low magnification (4×); more details about the preparation see in Methods. The two lines are strings from dental floss of the grid, holding down the slice in the experimental chamber. B) The same slice at higher magnification (40×) with patch pipette (black arrow) close to the neurone (white arrows). C) Fixation of the slice with formaldehyde (4%) after filling the neurone during whole cell recording with biocytin (0.2%) included in the patch pipette solution. Note the native axon of the sensory neurone (white arrows). Staining was visualized after incubating with the ABC-method (Avidin Biotinylated enzyme Complex).