Jorge A. Argibay

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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)
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)
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)
The effects of 100 microM ryanodine on the L-type calcium channel were studied using the pacth-clamp technique in isolated guinea pig ventricular myocytes. The inactivation kinetics of the calcium current were slowed down in the presence of ryanodine in agreement with the blockade of the release of calcium from the sarcoplasmic reticulum by the drug. The(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)
Antibodies directed against the second extracellular loop of G protein-coupled receptors have been shown to exert "agonist-like" activities. In order to test the hypothesis that this is a general phenomenon, antibodies were raised in rabbits against a synthetic peptide corresponding to the second extracellular loop of the newly sequenced human cardiac(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 have previously reported that antipeptide antibodies directed against the second extracellular loop of the cardiac h5-HT4 receptor could block the activation of the L-type Ca channel in human atrial cardiomyocytes. In this paper we investigate the immunological and physiological activity of these antibodies, in a cell system expressing a larger amount of(More)
The effects of cardiac glycosides (1 μM ouabain, 50 μM dihydrooubain, 1 μM strophanthidin) on Ca current (ICa) were investigated on Csloaded single frog ventricular cells using the wholecell patch-clamp technique (9). Cardiac glycosides exert both inhibitory and stimulatory effects on ICa in 20 Cs Ringer solution, but have only a stimulatory effect in O Cs,(More)