Fig. 5. Representative images of c-fos immunoreactive neurons in the ipsilateral spinal cord after paw incision for polylactic-coglycolic acid sheet (20 mg without lidocaine; control), slow-release lidocaine sheet (SRLS; 30%, 20 mg), or lidocaine (6 mg) groups. Increased c-fos expression was observed in the superficial internal area at 2 h (A ) and over a wide area at 48 h (D ) after paw incision. In the SRLS-treated group, a small number of c-fos–positive neurons was observed at all time points (B , E ). In the lidocaine-treated group, some c-fos expression was observed at 2 h (C ), but a wider area of c-fos expression was observed at 48 h (F ). Bilateral image of the spinal dorsal horn (G ). Scale bar = 100 μm.