Skip to main content


Fig. 4 | Molecular Brain

Fig. 4

From: NMDA receptor antagonists attenuate intrathecal morphine-induced pruritus through ERK phosphorylation

Fig. 4

Ketamine and ifenprodil attenuated morphine-induced pruritus and potentiated its analgesia. a Morphine-induced pruritus (M 0.5 μg or M 0.5 μg + DMSO) was obviously impaired by 1.0 μg ketamine or 0.1 μg ifenprodil. b Ketamine (1.0 μg) and ifenprodil (0.1 μg) significantly decreased the total number of scratches in 30 min that was induced by 0.5 μg morphine. c Time course of intrathecal morphine, intrathecal morphine + ketamine, and morphine + ifenprodil on morphine-induced analgesia over 2 h post-injection. Ketamine did significantly affect the time course of analgesia induced by intrathecal morphine. %MPE was elevated by ifenprodil at 30, 60, 90 and 120 min post-injection. d The effect of ketamine and ifenprodil on the AUC calculated based on %MPE in (c). Compared with the AUCs in the control groups (NS or DMSO), the AUCs in the morphine group, morphine + 1.0 μg ketamine group and morphine + 0.1 μg ifenprodil group were all significantly increased. Compared with the AUC in the 0.5 μg morphine group, the AUC in the 0.5 μg morphine + 0.1 μg ifenprodil group was significantly increased. Error bars represent SEM. *: p<0.05, compared to the NS or DMSO group. †: p<0.05, compared to the 0.5 μg morphine group or 0.5 μg morphine + DMSO group

Back to article page