Effects of honokiol and magnolol on NMDA-induced nociceptive responses and thermal hyperalgesia in mice. Honokiol (0.1-1.0 μg/paw), magnolol (0.1-1.0 μg/paw) and vehicle were intraplantarly administered 20 min prior to NMDA (150 μg) injection into hindpaw, and the total time spent licking the hindpaw was measured for 5 min after intraplantar injection of NMDA (A, B). The paw withdrawal latency in hot water at 47°C was measured during 5-120 min after intraplantar injection of NMDA (C, D). Each point represents the mean ± S.E.M. (n = 8-16). * indicates significantly different from vehicle group, *p < 0.05.