Pharmacologic isolation of sinoatrial activity from effects of neural excitation by use of tetrodotoxin.

Parasympathetic Responses in Hyperthyroid Rats. ALAN FRAZER AND MARILYN E. Hess 1 The Effects of Thyroxine on Rat Heart Adenosine 3’, 5’-Monophosphate, Phosphorylace b Kinase and Phosphorylase a Activity. Ai N FRAZER, MARILYN E. HESS AND JOSEPH SHANFELD 10 The Effect of Ouabain on Sodiumand Potassium-Activated Adenosine Triphosphatase from the Hearts of Several Mammalian Species. TAI AKERA, FRAN S. LARSEN AND THEODORE M. BRODY 17 Interactions of Acetylcholine and Epinephrine on Contractility, Glycogen and Phosphorylase Activity of Isolated Mammalian Hearts. JACOB A. BLUKOO-ALLOTEY, NORMA H. VINCENT AND SIDNEY ELLIS 27 The Effect of Dipyridamole on the Metabolism of Cardiac Muscle. DM HYON YU AND M. I. GLUCEMAN 37 The Mechanism of Action of Guanethidine on the Isolated Mammalian Heart. S. PLUCHINO, A. J. MUSKUS AND R. PLUCHINO 44 Chemical Sympathectomy of the Cat with 6-Hydroxydopamine. G. HAEUSLER, W. HAEFELY AND H. THOENEN 50 Mechanism of the Sympathomimetic Action of Cyclohexylamine and Hexylamine: Release of Catecholamines from Nerve Endings. ANDHEw S. WECHSLER, STEPHEN E. EPSTEIN AND GERALD GLICK 62 Blockade of Cardiac Effects of Isoproterenol by 4-(2-Hydroxy-3-Isopropylaminopropoxy)-Acetanilide (ICI 50,172). PITAMBAR SOMANI AND ATUL R. LADDU 72 Antiarrhythmic Actions of 4-(2-Hydroxy-3-Isopropylaminopropoxy)-Acetanilide (ICI 50,172) in the Dog Heart-Lung Preparation. ATUL R. LADDU AND PITAMBAR So-