Figure 2

Increased nocifensive behavior in the arthritis pain model is decreased by systemic (A) or intra-amygdala (B) administration of a CRF1 receptor antagonist. Mechanical stimuli (compression) of continuously increasing intensity were applied to the knee joint of adult male rats to measure hindlimb withdrawal thresholds. (A) Thresholds decreased 5–6 h postinduction of arthritis in the knee by intraarticular injections of kaolin/carrageenan (n = 5; P < 0.001, repeated measures ANOVA followed by Newman-Keuls Multiple Comparison Test). Systemic administration of NBI27914 (5 mg/kg i.p.; n = 5) significantly increased the hindlimb withdrawal thresholds at 45 min (P < 0.05) and 60 min (P < 0.01) after drug injection (repeated measures ANOVA followed by Dunnett's posthoc test). (B) Intra-CeA administration of NBI27914 (100 μM; concentration in microdialysis fiber; n = 7) also increased the hindlimb withdrawal thresholds of arthritic rats significantly (P < 0.05; repeated measures ANOVA followed by Newman-Keuls Multiple Comparison Test). Bar histograms show the mean ± SEM. * P < 0.05.