Peripheral nerve fibres in tail regenerates. (A) 1 month old tail regenerate. (B) Neurofilament 200 staining, enlarged view from the section in (A). Arrow indicates a neurofilament 200 positive nerve fibre. (C) Bright field image of a one week old tail regenerate, after DiI injection. (D) Red fluorescent image of (C), * marks the injection site of DiI, white arrow indicates a DiI-labelled nerve fibre. (E, F) The DiI signal is not found in neurons of the regenerating spinal cord (E) but is found in neurons of the proximal stump (red arrow in F). Arrow heads in (A-C) mark the amputation levels. Scale bars: 500 μm in (A-B); 250 μm in (C, D) and 20 μm in (E, F).