Naunyn-Schmiedeberg's archives of pharmacology
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Naunyn Schmiedebergs Arch. Pharmacol. · Aug 2005
Centrally mediated antihyperalgesic and antiallodynic effects of zonisamide following partial nerve injury in the mouse.
Some antiepileptic drugs are used clinically to relieve neuropathic pain. We have evaluated the effects and investigated the possible mechanisms of action of zonisamide, an antiepileptic drug, on thermal hyperalgesia and tactile allodynia in a murine chronic pain model that was prepared by partial ligation of the sciatic nerve. Subcutaneously administered zonisamide (10 and 30 mg/kg) produced antihyperalgesic and antiallodynic effects in a dose-dependent manner; these effects were manifested by elevation of the withdrawal threshold in response to a thermal (plantar test) or mechanical (von Frey) stimulus, respectively. ⋯ Moreover, the nitric oxide synthase inhibitor L-NAME, when injected either i.c.v. or i.t., potentiated the analgesic effects of zonisamide. In contrast, neither i.c.v. nor i.t. zonisamide produced antinociceptive effects against acute thermal and mechanical nociception in non-ligated mice. Together, following peripheral nerve injury, it appears that zonisamide produces centrally mediated antihyperalgesic and antiallodynic effects partly via the blockade of nitric oxide synthesis.