1. From the Department of Medical Physiology (H.V.M., H.J.J., J.M.T.d.B.), University Medical Center, Utrecht, the Netherlands; Institute of Genetics (D.E., J.D., M.T., T.O., K.W.), University of Bonn, Germany; and Interuniversity Cardiology Institute of the Netherlands (J.M.T.d.B.), Utrecht, the Netherlands. M.T. is presently at Howard Hughes Medical Institute, Center for Neurobiology and Behavior, Columbia University, New York, NY.