Spinal hyperalgesia following intrathecal with 1-DOPA in mice

Patients with Parkinsons disease frequently have 1-DOPAassociated leg pain. The pain is often lessened by additional administration with 1-DOPA. The present study was carried out to investigate 1-DOPA-induced hyperalgesia in mice. Male ddY mice were employed. Agents were injected intrathecally (i.t.) according to the method of Hylden & Wilcox. Inimediatly after the injection of 6 pmol substance P (SP), the number of responses consisting of licking and scratching directed toward the caudal part of the body were counted for 1min after the injection. The responses induced by SP reached 50.0±5.0 (mean±S.E.M.) counts. Coadministration of 10 nimol 1-DOPA with SP attenuated the responses to 6% (P