Milnacipran Inhibits Oxaliplatin-Induced Mechanical Allodynia through Spinal Action in Mice

We investigated whether milnacipran, a serotonin-noradrenaline reuptake inhibitor, would have therapeutic effect on oxaliplatin-induced mechanical allodynia in mice. A single intraperitoneal injection of oxaliplatin (3 mg/kg) induced mechanical allodynia, which peaked on day 10 after injection and almost completely subsided by day 20. Ten days post-oxaliplatin injection, the intraperitoneal administration of milnacipran (3-30 mg/kg) significantly and dose-dependently inhibited the established mechanical allodynia. Intrathecal injections of milnacipran (2.1-21 µg/site) also significantly and dose-dependently inhibited mechanical allodynia, but intracisternal and intracereboventricular injections at the same doses did not. The present results suggest that milnacipran is effective against oxaliplatin-induced mechanical allodynia and that the antiallodynic effect is mainly mediated by actions on the spinal cord.