Fig. 2

Acute CS1 therapy attenuates mechanical allodynia. The CS1 and scrambled (sCS1) peptides each dissolved in PBS (50 μg/ml in 5 μl) or PBS alone (5 μl) were administered by a single intraneural injection immediately after CCI (arrow). a von Frey testing for mechanical allodynia. Decline in the withdrawal threshold in the ipsilateral (ipsi) to CCI hind paw treated with PBS represents allodynia sustained for the study duration. sCS1 produced no significant change in the thresholds compared to PBS. In contrast, CS1-treated rats developed reduced sensitivity to tactile stimuli, compared to sCS1 (#) and PBS (*). Contralateral to injury, hind paws displayed no sensitivity to stimulus in either treatment group. The mean withdrawal thresholds (gram force; g) ± SEM of n = 6–17/group (* and #, p < 0.05, by ANOVA and Tukey’s post hoc test). b Hargreaves testing for thermal sensitivity. Withdrawal latency to thermal stimulation (radiant heat) decreased after CCI compared with prior to CCI (baseline). At the indicated days after CS1 and PBS injections, the sensitivity to thermal stimulation was not different between the groups. The mean paw withdrawal latency (seconds; s) ± SEM of n = 6/group