Allodynia and hyperalgesia evoked by sciatic mononeuropathy in NKI receptor knockout mice.

We have examined the participation of NK1 receptors in neuropathic pain by comparing behavioural responses after partial sciatic nerve ligation in wild-type (WT) and NK1 receptor knockout (KO) mice. Mechanical responses were tested with von Frey hairs, and cooling responses with acetone. WT and KO mice showed similar reactions before surgery. Nerve-ligated WT and KO mice showed equivalent spontaneous pain-related behaviour. Mechanical (mean threshold 20 +/- vs 9 +/- 1 mN) and cold allodynia (61 +/- vs 14 +/- 2 behaviours evoked by acetone) were significantly greater than in sham animals, but similar in WT and KO mice. We conclude that NK1 receptors are not essential for mechanical and cold allodynia evoked by partial nerve ligation.