1. Department of Chemistry, Lash Miller Laboratories, 80 St. George Street, University of Toronto, Toronto, Ontario, Canada M5S 3H6, Velocet Communications Inc., 210 Dundas St. West, Suite 810, Toronto, Ontario, Canada M5G 2E8, and Department of Pharmacology and Pharmacotherapy and Division of Cardiovascular Pharmacology (Hungarian Academy of Sciences and Szeged University), Szeged University, Dom ter12, Szeged, Hungary-6701