Calcium-antagonist effects of norbormide on isolated perfused heart and cardiac myocytes of guinea-pig: a comparison with verapamil

British Journal of Pharmacology
Sergio BovaR Padrini


1. Cardiac effects on norbormide and verapamil were compared in single ventricular myocytes, right atria, and Langendorff perfused hearts isolated from guinea-pigs. 2. In ventricular myocytes, norbormide 50 microM inhibited the peak calcium current (ICa) by 49.6 +/- 3.9% without altering the shape of the current-voltage relationship; verapamil 1 microM inhibited ICa by 83.2 +/- 3.3%. Neither norbormide nor verapamil affected ICa at the first beat after a 3 min quiescence period; during repeated depolarizations, both drugs cumulatively blocked ICa (use-dependence), with time constants of 23.0 +/- 7.0 s for norbormide and 91.3 +/- 8.4 s for verapamil. 3. In constant-flow perfused hearts electrically driven at 2.5 Hz or 3.3 Hz, both norbormide and verapamil concentration-dependently decreased ventricular contractility (dP/dtmax), atrio-ventricular (AV) conduction velocity and coronary pressure. Intraventricular conduction velocity was slightly decreased by norbormide but not by verapamil. At an equivalent change in AV conduction, norbormide depressed heart contractility less than verapamil. The effects of norbormide on AV conduction, intraventricular conduction, and contractility were frequency-dependent. Furthermore, the curves c...Continue Reading


Nov 14, 1977·Biochimica Et Biophysica Acta·L M Hondeghem, B G Katzung
Jan 1, 1989·Methods in Enzymology·M B De YoungA Scarpa
Jul 1, 1966·Journal of Medicinal Chemistry·G I PoosA P Roszkowski
May 4, 1984·European Journal of Pharmacology·T WangA Schwartz
Jan 1, 1983·Physiological Reviews·E O Feigl
Jan 1, 1983·Annual Review of Physiology·H L Stone
Mar 1, 1980·Canadian Journal of Physiology and Pharmacology·J Church, T T Zsotér

❮ Previous
Next ❯


Jun 12, 2003·European Journal of Pharmacology·Sergio BovaFabio Fusi
May 19, 2009·Canadian Journal of Physiology and Pharmacology·Meghan R MontTimothy P Geisbuhler
May 18, 2004·The Journal of Clinical Investigation·Martina J Sinnegger-BraunsJörg Striessnig
Apr 12, 2015·Vascular Pharmacology·Arianna CattelanAngelo Avogaro
May 22, 2004·Journal of Pharmacological Sciences·Maura FloreaniPaola Dorigo
Aug 23, 2012·Hepatology : Official Journal of the American Association for the Study of Liver Diseases·Alessia BortoluzziPaolo Angeli
Nov 13, 2008·Hepatology : Official Journal of the American Association for the Study of Liver Diseases·Giulio CeolottoPaolo Angeli
Jan 25, 2003·The Journal of Pharmacy and Pharmacology·Hajierah JamiePieter J Milne
Jan 19, 2007·Journal of Medicinal Chemistry·Iana VazzanaFabio Sparatore
Aug 18, 2006·Journal of Medicinal Chemistry·Emanuele CarosatiFrank J Devlin

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.

Cardiac Electrophysiology

Cardiac electrophysiology is the study of electrical activities of the heart and includes the assessment, diagnosis, and treatment of cardiac events. Find the latest research on cardiac electrophysiology here.


Arrhythmias are abnormalities in heart rhythms, which can be either too fast or too slow. They can result from abnormalities of the initiation of an impulse or impulse conduction or a combination of both. Here is the latest research on arrhythmias.

Anti-Arrhythmic Drug Therapies

Anti-arrhythmic drugs are used to prevent abnormal heart rhythms. These medications are used in conditions including, ventricular tachycardia, ventricular fibrillation and atrial fibrillation. Discover the latest research on anti-arrhythmic drug therapies here.

Antiarrhythmic Agents: Mechanisms of Action

Understanding the mechanism of action of antiarrhythmic agents is essential in developing new medications as treatment of cardiac arrhythmias is currently limited by the reduced availability of safe and effective drugs. Discover the latest research on Antiarrhythmic Agents: Mechanism of Action here.