Yves Tourneur

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The electrophysiological properties of dronedarone (SR33589), a noniodinated amiodarone-like agent, were studied on action potential (AP) and contraction of papillary muscle and on membrane ionic currents, Ca2+ transient, and shortening of ventricular cells of the guinea pig heart. In multicellular preparations, dronedarone (3, 10, and 30 microM) decreased(More)
The early phase of activation of the inward-rectifying potassium channel is studied on single cells from guinea-pig heart. The current is quasi-instantaneous when it is outward, but activates with time when it is inward. This relaxation is exponential and its time-constant decreases with hyperpolarization. TheI/V curve reflects a strong inward rectification(More)
OBJECTIVE To evaluate the cytotoxicity of iron nanoparticles on cardiac cells and to determine whether they can modulate the biological activity of 7-ketocholesterol (7KC) involved in the development of cardiovascular diseases. Nanoparticles of iron labeled with Texas Red are introduced in cultures of nonbeating mouse cardiac cells (HL1-NB) with or without(More)
1. In frog atrium, Cs ions block both the inward rectifieri K1 and the carbachol induced K currenti Cch. 2. Bothi K1 andi Cch display a high affinity for Cs with a K0.5 of 4×10−5 M fori k1 and of 8×10−5 M fori Cch atV=−50 mV. 3. Block of bothi K1 andi Cch is strongly voltage dependent. When fitted by the block model of Woodhull (1973), δ is >1 for the two(More)
Cell movement and spreading involve calcium-dependent processes and ionic channel activation. During bone resorption, osteoclasts alternate between spread, motile and resorptive phases. We investigated whether the electrical membrane properties of osteoclasts were linked to their membrane morphological changes. Rabbit osteoclasts were recorded by time-lapse(More)
Ventricular hypertrophy is associated with an increase in action potential (AP) duration which is potentially arrhythmogenic. The implication of the Na-Ca exchange current (I(Na-Ca)) in the lengthening of the AP is controversial. The role of this current in the increased duration of the low plateau of the AP in hypertrophied adult rat ventricular myocytes(More)
1.20 mM Cs+ ions reduce background current and decrease drastically the K+ depletion process, probably as a consequence of the reduction of iK1. The background current-voltage relationship becomes linear. 2. 20 mM Cs+ ions completely abolish the current induced by acetylcholine. 3. The possibility that the K+ current induced by acetylcholine is due to an(More)
After a Ca2+-free ouabain perfusion of 8-10 min duration, reperfusion of isolated stimulated frog auricular trabeculae with Ca2+ ouabain containing medium resulted in a large and transient contracture. The contracture was weaker in a quiescent preparation or in the absence of ouabain. In sodium-free (Li+ substitute) ouabain containing medium, the amplitude(More)
The present study discusses the role of structural organization of cardiac cells in determining the mechanisms of regulation of oxidative phosphorylation and interaction between mitochondria and ATPases. In permeabilized adult cardiomyocytes, the apparent K(m) (Michaelis-Menten constant) for ADP in the regulation of respiration is far higher than in(More)
HL-1, the first cell line with a cardiac phenotype for biological experiments, displays spontaneous electrophysiological and mechanical regular activity, and cyclic calcium movements. We isolated a derived line, devoid of transient movements, for confocal microscopy experiments. These cells do express cardiac proteins: connexin 43, the cardiac isoform of(More)