[1] Department of Pharmacology,
[2] University College London,undefined
[3] Gower Street,undefined
[4] London WC1E 6BT,undefined
[5] UK,undefined
[6] Fax: +44 20 7679 7298,undefined
[7] e-mail: e.assem@ucl.ac.uk ,undefined
[8] Department of Chemistry,undefined
[9] University College London,undefined
[10] 20 Gordon Street,undefined
[11] London WC1H OAJ,undefined
[12] UK ,undefined