B Pytkowski B Lewartowski

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UNLABELLED Activities of Ca(2+) -ATPase of sarcoplasmic reticulum (SERCA) and Na(+)/Ca(2+) exchanger (NCX) involved in cellular Ca(2+) turnover greatly change in hypertrophied and failing hearts. Unfortunately, contribution of these proteins as well as of the sarcolemmal Ca(2+)-ATPase (PMCA) to cellular Ca(2+) turnover has been investigated almost(More)
Decreased expression of sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA), overexpression of Na(+)/Ca(2+) exchanger (NCX) and diastolic SR Ca(2+) leak from the ryanodine receptors (RyRs) are believed to contribute to the decrease of myocyte contraction in failing heart. In this work we induced Ca(2+) leak through RyRs in isolated myocytes of guinea pig(More)
Isolated, superfused with [Ca2+]0 = 2.5-3 mM (T = 37 degrees C) and voltage clamped ventricular myocytes of guinea-pig hearts were stimulated by pulses from a holding potential -40 mV to +5 mV (duration 300 ms). They activated L-type Ca2+ current and a biphasic contractile response: a phasic component of amplitude approximately 7% of resting cell length(More)
Effect of Ni, Co and Mn ions and of D-600 on rested state contractions (RSCs) of cat and rabbit papillary muscles and on post rest contractions (PRCs) of cat and rabbit atrial muscle was investigated. Ni and Co in concentration 2 mmol/l reduced the force of RSCs in papillary muscles by 78%, increased the dip between the phase 1 and 2 of respective action(More)
The rest- and excitation-dependent shifts of Ca and45Ca in the isolated, perfused ventricles of guinea-pig hearts were investigated. As much as 50% of the total Ca content (2.2 mmol/kg ww) found in the ventricular muscle stimulated at a steady rate of 60/min, was released into perfusate during 4 min of rest. In the preparations perfused with45Ca containing(More)
Taking advantage of the unique model of slowly developing dilated cardiomyopathy in mice with cardiomyocyte-specific transgenic overexpression of activated Gαq protein (Tgαq*44 mice) we analyzed the contribution of the cardiomyocyte malfunction, fibrosis and cytoskeleton remodeling to the development of heart failure in this model. Left ventricular (LV) in(More)
Isolated perfused guinea pig heart ventricles were rendered quiescent by means of atrioventricular block and elevation of perfusate potassium concentration to 7.4 mM. Muscles were exposed to 45Ca2+ during 3 min of rest followed by a single or multiple excitations. Tissue analysis after a half minute of nonradioactive perfusion showed that the 45Ca content(More)
The experiments undertaken in an attempt to localize the site of the inotropic action of acetylcholine on cardiac muscle were performed on canine and rabbit isolated left auricles. Simultaneous recordings were made of intracellular action potentials and contractile strength of electrically driven atria perfused with Tyrode solution. Acetylcholine added to(More)