Efficacy of nociceptin inhibition on WDR neuron activity is enhanced in mononeuropathic rats.

Nociceptin (NC), administered microiontophoretically at different concentrations, significantly reduced the spontaneous and stimulus-evoked activity on WDR neuron in rats with chronic constriction of one sciatic nerve and showing signs of neuropathic pain. The effect was not antagonized by Naloxone. The same concentrations of NC were ineffective on the noxious stimulus evoked responses of WDR neurons in sham and intact rats.

The mGluR5 selective antagonist 6-methyl-2-(phenylethynyl)-pyridine reduces the spinal neuron pain-related activity in mononeuropathic rats.

In rats with chronic constriction of one sciatic nerve (CCI rats), showing behavioural signs of neuropathic pain, 6-methyl-2-(phenylethynyl)-pyridine (MPEP), a selective mGluR5 antagonist, was intraperitoneally administered at 0.75, 1.0 and 1.