Fig. 3

Lidocaine-induced sensory blockade attenuates the impairment of 3CSRTT performance induced by acute inflammatory pain. A Schematic of lidocaine injection into the popliteal space and representative images of the sciatic nerve region after injection of 50 μL fast green. B Concentration-dependent time-to-event survival curves for offsetting mouse sciatic nerve motor block due to lidocaine injection. The offset time was defined as when the animal regained its ability to use the treated hind limb to hang on to the inverted mesh. (n = 10 per group). C Experimental design. Mice were pretreated with either saline or lidocaine in the popliteal space and then injected with 2% formalin. The time spent licking the injected paw was measured for 60 min after formalin injection (n = 5 mice per group). D Time spent licking the paw following saline/formalin or lidocaine/formalin injection displayed in 5-min time bins. E–K The effect of lidocaine-induced sciatic nerve blockade on formalin-induced impairment of 3CSRTT performance. E Experimental design. Mice were pretreated with either saline or lidocaine into the popliteal space and then injected with 2% formalin (saline/formalin group or lidocaine/formalin group), and a 60-min 3CSRTT was performed following formalin injection. F, G Correct (F) and omission (G) in the 3CSRTT of each group over the 60-min testing period. Data points are displayed in 5-min time bins. H, I Correct response latency (H) and reward latency (I) in the 3CSRTT of each group over the 60-min testing period. J, K Correct (J) and omission (K) in the 3CSRTT of each group in phases 1 and 2 (n = 7 mice per group). Data are mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001. Survival fractions were calculated using the product limit (Kaplan–Meier) method; the survival curves were compared with the log-rank test (C). Two-way ANOVA followed by the Sidak’s multiple comparisons test in D, F and G and two-tailed unpaired t test in H–K