[1] ST THOMAS HOSP,SCH MED,SHERRINGTON SCH PHYSIOL,DEPT PHYSIOL,LONDON SE1 7EH,ENGLAND
[2] DEPT PHARMACOL,NEUROANAT NEUROPHARMACOL GRP,OXFORD,ENGLAND
[3] DEPT HUMAN ANAT,OXFORD,ENGLAND
[4] ST THOMAS HOSP,SCH MED,DEPT BIOCHEM,LONDON SE1 7EH,ENGLAND
[5] MCGILL UNIV,DEPT PHARMACOL & THERAPEUT,MONTREAL H3A 2T5,QUEBEC,CANADA
[6] HARVARD UNIV,SCH MED,DEPT NEUROBIOL,BOSTON,MA 02115