Figure 5.

Repeated intrathecal injections of ML221 delays the development and partially reverses the maintenance of CCI-induced neuropathic pain. Repeated administration of ML221 (10 µg) for 3 consecutive days (day 0–2) in the early phase delayed the onset of (A) mechanical allodynia and (B) thermal hyperalgesia. Behavioral tests were performed 1 day prior to CCI surgery and 1, 3, 5, 7, 9, 11, 13 and 15 days post-surgery. Repeated injections of ML221 (10 µg) for 3 consecutive days (day 7–9) in the later phase significantly alleviated CCI-induced (C) mechanical allodynia and (D) thermal hyperalgesia. A total of eight rats were included in each group. Data are presented as the mean ± standard error of the mean. Data were analyzed using two-way analysis of variance. **P<0.01 vs. CCI + DMSO group. CCI, chronic constriction injury; DMSO, dimethyl sulfoxide.