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. Author manuscript; available in PMC: 2015 Sep 1.
Published in final edited form as: Pain. 2014 Jun 28;155(9):1878–1887. doi: 10.1016/j.pain.2014.06.019

Figure 2.

Figure 2

Extracellular spike activity in the spinal dorsal horn 7 days after facet capsule injury. (a) Traces indicate the filament application, raw extracellular voltage recording, and neuron identification and spike counts. Neuronal firing was sorted and spikes were counted during a baseline period and mechanical stimulation of the forepaw; a representative response to five applications of a 26g von Frey filament 7 days after facet capsule injury is shown. (b) Firing increases after injury (inj-VEH0h) over sham (sham-VEH0h) during light brush, 4g, 10g, and 26g von Frey filament stimulation (*p<0.026). Immediate bupivacaine attenuates firing in response to all stimuli after injury (#p≤0.004). Bupivacaine treatment (inj-BP0h) also reduces activity below that of sham for brush, pinch, and the 1.4g von Frey filament (^p<0.0007). (c) During all stimuli, for injections at day 4, neuronal firing is increased over sham (sham-VEHd4) after injury with either vehicle injection (inj-VEHd4) (*p<0.045) and after bupivacaine injection (inj-BPd4) (^p<0.035).