[1] Royal Free & Univ Coll Med Sch, Auton Neurosci Ctr, London NW3 2PF, England
[2] Univ Milan, Lab Mol & Cellular Pharmacol Purinerg Transmiss, Dept Pharmacol Sci, I-20133 Milan, Italy
[3] Univ Manchester, Fac Life Sci, Manchester M13 9PT, Lancs, England
[4] ASCR, Inst Expt Med, Prague 14220, Czech Republic
[5] Goethe Univ Frankfurt, Bioctr, Inst Cell Biol & Neurosci, D-60439 Frankfurt, Germany