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

Abstract

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

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Citations

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

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