Fig. 5.

Abnormal electrophysiological properties of WDR neurons in HSE-RFP reporter-expressing dorsal horns of the spinal cord after sciatic nerve injury. (A) (left) Schematic of in vivo electrophysiological recording of WDR neurons in the lumbar spinal segments (L2-3 levels) at 4 weeks after injury. A bracket indicates the target recording region in the laminae III-VI in the dorsal horn ipsilateral to the injury. (Right) Tissue section adjacent to the recording site, showing HSE-RFP reporter expression throughout the dorsal horn, with the highest in the superficial region. Broken lines demarcate the boundaries of different laminae (I–IV). Bar = 100 μm. (B–G) Spontaneous discharge of wide-dynamic range (WDR) neurons in the ipsilateral dorsal horn of the spinal cord at the lumbar level (see the detail in Experimental Procedures) in control (B–D) and the SNI (E–G) mice 4 weeks after injury. The results are displayed in waveforms and spike-frequency histograms recording for 30 s (B and E), individual waveform (C and F), and superimposed waveforms obtained in 1 s (D and G), indicating increased firing following sciatic nerve injury. (H) Firing frequency of WDR neurons in SNI mice is significantly higher than that in sham control mice. *p < 0.05 by Mann-Whitney U test (n = 16 neurons from 4 animals per group). Mean ± SD is presented.