Effect of JTC-801 (nociceptin antagonist) on neuropathic pain in a rat model.

JTC-801, a nociceptin antagonist, may alleviate neuropathic pain because nociceptin has been shown to produce pain modulation. We report that JTC-801 alleviates heat-evoked hyperalgesia and investigated the possible protective effect on osteoporosis induced by chronic constriction injury (CCI) in rats. JTC-801 was given orally to rats with CCI at 0% (vehicle), 0.03% (low dose), or 0.06% (high dose) in food. Paw withdrawal latency (PWL) to heat, bone mineral content (BMC) and bone mineral density (BMD) of the whole tibial bone were measured. JTC-801 dose-dependently normalized PWL. Although JTC-801 did not inhibit a CCI-induced decrease in BMC and BMD, it inhibited an increase in the number of osteoclasts in the JTC-801 groups. JTC-801, given orally in food, alleviated heat-evoked hyperalgesia in CCI rats, suggesting that it is useful for the treatment of neuropathic pain.