Figure 4.

N-ethylglycine (EG) reduces nociceptive behavior in inflammatory pain. (A), Behavioral data in adult mice after induction of inflammatory pain by injection of complete Freund's adjuvant (5 μL) in the left hind paw expressed as 50% withdrawal threshold (in g). EG (200 mg/kg), the known GlyT1 substrate sarcosine (Sar, 200 mg/kg), or saline was applied subcutaneously after allodynia had developed 3 days after induction (marked with arrow). Assessment of mechanical allodynia was performed with von Frey hairs at indicated time points. Please note that the treatment was repeated at 48 hours after initial treatment (marked with arrow) to test whether the effects can be achieved again. Data are expressed as mean ± SEM; n = 8 per group; *P < 0.05 vs control group (saline); 2-way repeated-measures analysis of variance and Bonferroni post hoc test. (B), Corresponding data from complete Freund's adjuvant–untreated right hind paws. (C), Inflammatory edema was assessed by means of paw thickness (mm) 24 hours after first treatment with EG. Data are expressed as mean ± SEM; n = 8 per group; no significant differences were detected between treatment groups; 1-way repeated-measures analysis of variance and Bonferroni post hoc test.