Figure 2. Effects of L-NAME and L-arginine on sleep latency (A) and REM sleep latency (B) in an orofacial pain model induced by Freund’s adjuvant injected into the temporomandibular joint during 2 light periods of recording. The values are expressed as mean ± SD. *Differ from the other groups (p < 0.001, ANOVA, Tukey test). N = 8/group.