Figure 4.

Dorsal root ganglion (DRG) injection induces a smaller transient peripheral sensitization than that induced by spared nerve injury (SNI). (a) Von Frey measurements of mechanical thresholds from hindpaws of SNI rats (n = 5) versus rats that are DRG-injected with AAV-GFP (n = 5) over the examined time course. Both DRG injection and SNI significantly reduced mechanical thresholds (P < 0.05). However, sensitization due to DRG injection was significantly smaller than that due to SNI (P < 0.05). (b) Measurements of heat hyperalgesia using the Hargreaves apparatus for SNI rats (n = 5) versus rats that are DRG-injected with AAV-GFP (n = 5) over the examined time course. No significant change was observed. Data are presented as means ± SEM. AAV, adeno-associated virus; GFP, green fluorescent protein.