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. 2010 Aug 11;30(32):10860–10871. doi: 10.1523/JNEUROSCI.1980-10.2010

Figure 2.

Figure 2.

Acute pain behavior and in vivo electrophysiology of wide dynamic range (WDR) in Dicer mutant mice. A, Rotarod studies showed no motor deficits in conditional Dicer-null animals (n = 12, WT; n = 20, KO). B, Acute mechanical pressure applied with the Randall–Selitto apparatus demonstrated identical behavior in KO and WT mice (n = 12, WT; n = 20, KO). C, Responses to low-threshold mechanical stimulation by Von Frey filaments are normal in the null mutants (n = 8, WT; n = 15, KO). D, Hargreaves' apparatus demonstrates identical latencies of response to thermal stimulation (n = 8, WT: n = 16, KO). E, Supra-spinal reflexes to heat (50 and 55°C) using the hot plate apparatus demonstrates identical latencies in KO and WT mice (n = 9, WT; n = 14, KO). F, Cold behavior (number of liftings) is reduced in the Dicer-null mutant mice (0°C) using the cold plate apparatus (n = 16, WT; n = 22, KO). G, A-fiber and C-fiber firing thresholds of WDR neurons in control Nav1.8Cre+/− mice (black) (n = 14) and Dicer KO mice (white) (n = 16). H, Responses to transcutaneous electrical stimulation of the receptive field (a train of 16 2-ms-wide electrical pulses at 0.5 Hz at 3× C-fiber threshold). Spikes evoked between 0 and 50 ms were classified as evoked by A-fiber input, and those evoked between 50 and 250 ms were classified as evoked by C-fiber input. Postdischarge (PD) describes the spikes that are evoked between 250 and 800 ms and correlate with C-fiber activity. Input is determined by the first stimulus of the train × 16 and reflects nonpotentiated C-fiber-evoked WDR neuron responses. Wind-up (WU) is determined by calculating additional spikes above the predicted constant baseline response and describes the increased neuronal excitability evoked by C-fibers to repeated constant stimulation. C-fiber activity, wind-up, and postdischarge were all significantly decreased in diphtheria toxin A chain (DTA) mice. I, Evoked responses from innocuous dynamic brush, noxious pinch, and a cold (1°C) water jet stimulus. J, Evoked responses from Nav1.8 Cre+/− mice (solid line) and Dicer−/− mice (dashed line) to graded von Frey filaments. K, Thermally evoked responses using water jets at graded temperatures (Temp). There was no significant difference between the two groups.