The rat with spontaneous genetic hypertension is not a suitable model of human essential hypertension.

Brief Reviews: Lipid-Membrane Interactions and the Pathogenesis of Ischemic Damage in the Myocardium. Arnold M. Katz and Frank C. Messineo 1 Role of Changes in Microsomal Calcium Uptake in the Effects of Reperfusion of Ca-Deprived Rat Hearts. Lauri E. Alto and Naranjan S. Dhalla 17 Reduction of Maximal Coronary Vasodilator Capacity in Conscious Dogs with Severe Right Ventricular Hypertrophy. Paul A. Murray and Stephen F. Vatner 25 Decreased Vascular and Increased Adrenal and Renal Sensitivity to Angiotensin II in the Newborn Lamb. Sharon R. Siegel 34 The Discontinuous Nature of Propagation in Normal Canine Cardiac Muscle: Evidence for Recurrent Discontinuities of Intracellular Resistance that Affect the Membrane Currents. Madison S. Spach, Walter T. Miller, III, David B. Geselowitz, Roger C. Barr, J. Mailen Kootsey, and Edward A. Johnson 39 pH-Dependent Electrophysiological Effects of Quinidine and Lidocaine on Canine Cardiac Purkinje Fibers. Stanley Nattel, Victor Elharrar, Douglas P. Zipes, and John C. Bailey 55 Effects of Cholinergic Nerves on Cerebral Blood Flow in Cats. David W. Busija and Donald D. Heistad 62 Effects of Intracoronary Administration of Bradykinin on the Impulse Activity of Afferent Sympathetic Unmyelinated Fibers with Left Ventricular Endings in the Cat. Federico Lombardi, Paolo Delia Bella, Rodolfo Casati, and Alberto Malliani 69 Regional Myocardial Blood Flow during Exercise in Dogs with Chronic Left Ventricular Hypertrophy. Robert J. Bache, Thomas R. Vrobel, W. Steves Ring, Robert W. Emery, and Robert W. Andersen 76 Intravenous Bovine Testicular Hyaluronidase Depolymerizes Myocardial Hyaluronic Acid in Dogs with Coronary Artery Occlusion. Robert A. Wolf, Lee-Yuh Chaung, James E. Muller, Robert A. Kloner, and Eugene Braunwald 88 Inhibition by Free Radical Scavengers and by Cyclooxygenase Inhibitors of Pial Arteriolar Abnormalities from Concussive Brain Injury in Cats. Enoch P. Wei, Hermes A. Kontos, W. Dalton Dietrich, John T. Povlishock, and Earl F. Ellis 95 Regulation of the Postsynaptic a-Adrenergic Receptor in Rat Mesenteric Artery. Effects of Chemical Sympathectomy and Epinephrine Treatment. Wilson S. Colucci, Michael A. Gimbrone, Jr., and R. Wayne Alexander 104 /8-Adrenergic Regulation of Total Systemic Intravascular Volume in the Dog. David L. Rutlen, Edward N. Supple, and Wm. John Powell, Jr 112 Regional Edema Formation in Isolated Perfused Dog Lungs. Charles A. Hales, David J. Kanarek, Bhagwat Ahluwalia, Alexander Latty, John Erdmann, Shahrokh Javaheri, and Homayoun Kazemi 121 Developmental Aspects of the Renal Response to Hypoxemia in the Lamb Fetus. Jean E. Robillard, Richard E. Weitzman, Leon Burmeister, and Fred G. Smith, Jr 128 Vasoactive Intestinal Polypeptide and the Canine Cerebral Circulation. David A. Wilson, John T. O'Neill, Sami I. Said, and Richard J. Traystman 138 Instructions to Authors 149 News from the American Heart Association 152