[1] Univ Coll London UCL, Wolfson Inst Biomed Res WIBR, Mol Nocicept Grp, London WC1E 6BT, England
[2] Queen Mary Univ London, William Harvey Res Inst, Barts & London Sch Med & Dent, London, England
[3] Univ Sheffield, Dept Biomed Sci, Sheffield S10 2TN, S Yorkshire, England
[4] AstraZeneca, BioPharmaceut R&D, Neurosci Discovery Ctr, Biomed Campus,1 Francis Crick Ave, Cambridge CB2 0AA, England