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1. Effect of isoproterenol on 85Sr accumulation in the myocardium of the rat during postnatal ontogeny

Creator:
Ošťádalová, I. and Ošťádal, B.
Type:
article, model:article, and TEXT
Subject:
isoproterenol, strontium, rat heart, and development
Language:
English
Description:
The aim of this study was to establish whether administration of toxic doses of isoproterenol (IPRO) increases the accumulation of strontium - a homologue element of calcium - in the rat heart during postnatal development. It has been shown that in 14-day-old animals “Sr uptake was not increased; starting from the 30th day of postnatal life this parameter increases significantly up to adulthood.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Electrocardiography in two models of isoproterenol-induced left ventricular remodeling

Creator:
Eva Kráľová, Mokráň, T., Ján Murín, and Tatiana Stankovičová
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Experimentální medicína, kardiovaskulární fyziologie, elektrokardiografie, potkan, cardiovascular physiology, electrocardiography, Rattus norvegicus, isoproterenol, ventricular remodeling, 14, and 616-092
Language:
English
Description:
We studied the ability of the ECG to detect pathological changes in isoproterenol-induced remodeling of rat heart. Myocardial hypertrophy in rats was induced by repeated injections of isoproterenol (5 mg/kg s.c. 7 days, Iso5, n=7). Single overdose of isoproterenol (150 mg/kg s.c., Iso150, n=7) evoked myocardial infarction followed with ventricular remodeling. The electrocardiograms were recorded in anesthetized animals (thiopenthal 45 mg/kg i.p.) and myocardial contractile performance was analyzed in isolated hearts perfused according to Langendorff. The hypertrophic hearts were characterized by increased heart and left ventricular (LV) weight as well as by thicker LV free wall and interventricular septum. Mean values of LV contraction did not significantly differ from controls. Longer QT interval, QRS complex, negative Q and S waves, higher R amplitude were typical characteristics for Iso5 rats. Iso150 animals showed tendency to decreased systolic blood pressure and heart frequency. Decrease in the thickness of LV compared to Iso5 as well as impaired LV function were related to the dilated left ventricle. Iso150 ECG showed longer QRS and QT, deepened negativity of S wave and mild decrease of RII compared to Iso5. Voltage criteria showed that Sokolow-Lyon index is a good predictor of left ventricular hypertrophy in isoproterenol-induced cardiac remodeling without systemic hypertension., E. Kráľová, T. Mokráň, J. Murín, T. Stankovičová., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Partially phosphorylated phosphorylase in the rat heart after β-receptor stimulation in vivo

Creator:
Kuželová-Belanová, M., Vereb, G., and Švec, P.
Type:
article, model:article, and TEXT
Subject:
glycogen phosphorylase, phosphorylase ab hybrid, isoproterenol, protein phosphorylation, and rat heart
Language:
English
Description:
The formation of the phosphorylase ab hybrid and its further transformation into phosphorylase a has been demonstrated in the rat heart after different periods of i.v. isoproterenol administration. Phosphorylase ab hybrid was determined in the presence of AMP and/or caffeine. Only the partially phosphorylated phosphorylase was found in the control rat hearts and its activity was 30 % of the total phosphorylase. The phosphorylase ab hybrid was disclosed particularly after small isoproterenol doses (0.031 -0.062 /rg.kg-1) and at short time interval (15 s) after its administration. Higher isoproterenol doses (0.25-0.5 ¿/g.kg-1) changed the partially phosphorylated phosphorylase to phosphorylase a (58 %) after a longer time interval (40 s), The phosphorylase ab hybrid was revealed even at the maximal rate of stimulation. The formation of the phosphorylase ab hybrid in the rat heart in vivo appears to be of physiological significance. Our results confirmed the earlier suggestion that the -AMP/-f AMP activity ratio reflects the percentage proportion of the phosphorylated subunits of phosphorylase but not of the activated phosphorylase molecules.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Phosphodiesterases inhibition enhances the effect of glucagon on cardiac automaticity in the isolated right ventricle of the rat

Creator:
Gonzalez-Muñoz, C. and Hernández, J.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, glukagon, glucagon, cyclic nucleotide phosphodiesterases (PDE), cardiac automaticity, isoproterenol, 14, and 612
Language:
English
Description:
We evaluated the effect of glucagon on cardiac automaticity as well as the possible role of cyclic nucleotide phosphodiesterases (PDE) in regulating this effect. Concentration response curves for glucagon in the absence and in th e presence of the non-selective PDE inhibitor IBMX were performed in the isolated right ventricle of the rat. We found that glucagon produces only a minor increase of ventricular automa ticity (11.0±4.1, n=5) when compared to the full agonist of β-adrenoceptor isoproterenol (182.2±25.3, n=7). However, IBMX enhances the maximal efficacy of glucagon on cardiac automaticity (11.0±4.1, in the absence and 45.3±3.2 in the presence of IBMX, n=5, P<0.05). These results indicate that PDE blunts proarrhythmic effects of glucagon in rat myocardium., C. Gonzalez-Muñoz, J. Hernández., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public