GABA, but not opioids, mediates the anti-hyperalgesic effects of 5-HT7 receptor activation in rats suffering from neuropathic pain

► 5-HT7 receptor agonists reduced mechanical hyperalgesia in sciatic nerve-ligated rats. ► Intrathecal bicuculline blocked 5-HT7R-mediated antihyperalgesia in neuropathic rats. ► 5-HT7R-mediated antihyperalgesia is unaffected by spinal opioid receptors blockade. ► Both spinal and supraspinal processes contributed to 5-HT7R-mediated antihyperalgesia.