Antinociceptive effect of the novel compound OT-7100 in a diabetic neuropathy model

We previously reported that OT-7100 (5-n-butyl-7-(3,4,5-trimethoxybenzoylam ino)pyrazolo[1,5-alpha-]pyrimidine) had antinociceptive potency in various animal models. To further characterize this compound, the present study exa mined the effects of OT-7100 on mechanical hyperalgesia and motor nerve con duction velocity in streptozotocin-induced diabetic rats. OT-7100 significa ntly increased the nociceptive threshold in the diabetic rat in a dose-depe ndent manner. Gabapentin (anticonvulsant agent) and insulin strongly increa sed the nociceptive threshold but gabapentin increased it above normal leve ls. An aldose reductase inhibitor slightly increased the nociceptive thresh old at a high dose. We also measured glucose levels and motor nerve conduct ion velocity in OT-7100-treated rats. Insulin decreased glucose levels but OT-7100 had no effect on glucose levels or on motor nerve conduction veloci ty. These results suggest that OT-7100 alleviates hyperalgesia in a diabeti c neuropathy model in a different manner from gabapentin or aldose reductas e inhibitor and may be a new treatment for the pain associated with periphe ral nerve injury. (C) 2001 Elsevier Science BN. All rights reserved.