Spinal activation of delta opioid receptors alleviates cancer-related bone pain

▶In rats, bone cancer induced mechanical allodynia and bone fragilization. ▶Delta opioid receptor agonist deltorphin injected intrathecally reduced cancer pain. ▶The analgesic effect of deltorphin was blocked by naltrindole. ▶Analgesic efficacy of deltorphin was similar for bone cancer and inflammatory pain.