[1] United Med & Dent Sch Guys & St Thomas Hosp, Guys Hosp, Div Biochem & Mol Biol, Biochem Neuropharmacol Grp, London SE1 9RT, England
[2] Royal London Hosp, London Hosp, Coll Med, Dept Neurol, London E1 1BB, England
[3] United Med & Dent Guys & St Thomas Hosp, St Thomas Hosp, Div Physiol, London SE1 9RT, England