Single administration of OXA (2 mg/kg, i.p.) significantly increased the time of elevating and licking of the hind paw in response to acetone stimulation, from 1 to 10 days after the administration, compared to the vehicle administration group. We used mice on 4 days after OXA administration. I.t. injection of PACAP 6-38 (peptide antagonist of PACAP receptor, 0.1 nmol) and PA-8 (0.1-10 nmol) ameliorated the OXA-induced cold allodynia, suggesting that spinal PAC1 receptor is involved in the OXA-induced cold allodynia. Next, we examined the effects of systemic administration of PA-8, PA-810 and PA-81004 on OXA-induced cold allodynia. As a result, both intraperitoned and oral administration (3-30 mg/kg) dose-dependently alleviated the OXA-induced cold allodynia. The present results suggest that PA-8, PA-810 and PA-81004 may become oral active analgesics against chemotherapy-induced peripheral neuropathy.