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1. Ca2+ currents were measured in single cells isolated from frog ventricle using the whole-cell patch clamp technique and a perfused pipette. K+ currents were blocked with intracellular (120 mM) and extracellular (20 mM) Cs+. 2. A single type of Ca2+ current (ICa) was found in these cells. The current activated at voltages positive to -30 mV, exhibited a(More)
Contractile responses of left extrapulmonary artery segments with either intact or damaged endothelium were examined with changes in PO2 at constant pH. Hypoxia consistently reduced noradrenaline-induced contractions. This hypoxia-induced relaxation was sometimes followed by a contraction and a second relaxation. Hypoxia-induced relaxations were also(More)
We show that gadolinium (Gd3+) is a potent calcium channel blocker in guinea-pig isolated ventricular myocytes. A dose-dependent inhibition of ICaL was found with an EC50 of 1.4 microM and a complete inhibition at 10 microM Gd3+. When compared with Cd2+, it appeared that the blockade of ICaL is a complex phenomenon probably involving more than one site of(More)
The 52-kDa SSA/Ro (Ro52) ribonucleoprotein is an antigenic target strongly associated with the autoimmune response in mothers whose children develop neonatal lupus and congenital heart block. When sera from patients with systemic lupus erythematosus were used as autoimmune controls in an enzyme immunoassay to screen for antibodies against the human(More)
Antibodies directed against a peptide corresponding to the second loop of the human beta2-adrenergic receptor were induced in rabbits by immunisation with the free peptide in complete Freund's adjuvant. The resulting antibodies were affinity-purified and shown to be monospecific for the target receptor. They were able to stimulate the L-type Ca2+ channels(More)
Sera from T. cruzi infected mice were tested in an enzyme immunoassay on peptides corresponding to the second extracellular loops of the β−, the β2-adrenergic receptor and the M2 muscarinic receptor. All sera of mice (4/4) in the acute phase recognized the β1-adrenergic receptor and the M2 muscarinic receptor peptides but not the β2-adrenergic receptor(More)
1. The cardiotonic effect of heptaminol hydrochloride (Hept-a-myl, Delalande) was studied using 31P-nuclear magnetic resonance (n.m.r.) spectroscopy and left ventricular pressure (LVP) measurements in rat isolated hearts. The possibility of this effect being mediated by an intracellular realkalinisation was tested. 2. Isolated hearts were perfused at 10 ml(More)
1. The effect of ruthenium red on calcium and sodium currents was studied in guinea-pig isolated ventricular heart cells with the whole cell patch-clamp technique. 2. Ruthenium red very efficiently blocked the L-type calcium current in a dose-dependent manner. A significant block was observed for concentrations as low as 0.3 microM. Analysis of the(More)
In human atrial myocytes, serotonin rather than sympathetic, stimulation is more frequently associated with atrial fibrillation. So does the arrhythmogenic effect of serotonin result from the mechanism of action of the receptor or the context of its action upon cardiac myocytes? The capacity of agonists to produce cAMP followed the sequence 5-HT < Iso <(More)