1. From the Institute of Physiology (F.K., T.R., T.G., U.P.), Clinic of Anaesthesiology (M.A.B.), and Cardiology Division (H.-Y.S.), Medizinische Poliklinik–Innenstadt, Ludwig-Maximilians-University, Munich, Germany; and the Department of Pharmacology and Toxicology (K.N., W.B.C.), Medical College of Wisconsin, Milwaukee, Wisc.