1. Biomedical Research Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee DDI 9SY, Scotland, U.K.
2. C.J. Henderson and C.R. Wolf are Members of the ICRF Molecular Pharmacology Unit within the Biomedical Research Centre. Pharmacology Unit Withtal and Medical School, University of Dundee
3. RZeneca Central Toxicology Laboratory, Alderley Park, Macclesfield, Cheshire SK10 4TJ, U.K.
4. Centre for Tsukuba Advanced Research Alliance and Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba 305-8577, Japan