Figure 3. Effects of L-NAME and L-arginine on the percentage of NREM sleep (A) and REM sleep (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). Panel B: # Differs from ‘untreated orofacial pain’ and ‘treated with L-arginine’ groups (p < 0.001, Tukey test). N = 8/group.