1. From the Department of Physiology (Z.B., W.L., T.H.N., A.K., G.K.), New York Medical College, Valhalla, NY; the Department of Pathophysiology (A.K.), Semmelweis University, Budapest, Hungary; and the Division of Clinical Physiology Z.B., N.E., A.T.), Institute of Cardiology, University of Debrecen, Debrecen, Hungary.