We compared the effects of endothelin-1 (ET-1) on intracellular pH, intracellular [Ca 2 1 ] i , and cell contraction in hypertrophied adult ventricular myocytes from ascending aortic banded rats and age-matched controls. Intracellular pH (pH i ) was measured in individual myocytes with SNARF-1, and [Ca 2 1 ] i was measured with indo-1, simultaneous with cell motion. Experiments were performed a...

It is unclear whether muscle activity reduces or increases Na(+)-K(+)-ATPase maximal in vitro activity in rat skeletal muscle, and it is not known whether muscle activity changes the Na(+)-K(+)-ATPase ion affinity. The present study uses quantification of ATP hydrolysis to characterize muscle fiber type-specific changes in Na(+)-K(+)-ATPase activity in sarcolemmal membranes and in total membran...

The contribution of a voltage-sensitive release mechanism (VSRM) for sarcoplasmic reticulum (SR) Ca2+ to contraction was investigated in voltage-clamped ventricular myocytes at 37°C. Na+ current was blocked with lidocaine. The VSRM exhibited steady-state inactivation (half-inactivation voltage: -47.6 mV; slope factor: 4.37 mV). When the VSRM was inactivated, contraction-voltage relationships we...

The present study was undertaken to examine cardiac responses to some of the temperature challenges that eels encounter in their natural environment. The contractile properties of ventricular muscle was studied on electrically paced tissue strips after long term acclimation at 0 °C, 10 °C, or 20 °C, and following acute ± 10 °C temperature changes. The time-course of contraction, and thus maxima...

In this paper, we present a new concept of random contraction and prove a coupled random fixed point theorem under this condition which generalizes stochastic Banach contraction principle. Finally, we apply our contraction to obtain a solution of random nonlinear integral equations and we present a numerical example.

The activity of the cardiac Na +-Ca 2+ exchanger (NCX1.1) undergoes continuous modulation during the contraction/relaxation cycle due to the accompanying changes in the electrochemical gradients for Na + and Ca 2+. In addition, NCX1.1 activity is also modulated via secondary, ionic regulatory mechanisms mediated by Na + and Ca 2+. In an effort to evaluate how ionic regulation influences exchang...

this article is an attempt to survey the contraction and cancellation of the reuter’s agreement as a one-sided approach and from special perspective, by using minimalistic ideology and with emphasis on multi-sided and various reasons and factors effective in the process of this contract.  on the basis of this research, in this contraction, different factors came together and augmented one anoth...

The inotropic effects of ACh and adenosine on ferret ventricular cells were investigated with the action potential-clamp technique. Under current clamp, both agonists resulted in action potential shortening and a decrease in contraction. Under action potential clamp, both agonists failed to decrease contraction substantially. In the absence of agonist, application of the short action potential ...

Omelchenko, Alexander, Ron Bouchard, Sabin Shurraw, Michael Trac, Mark Hnatowich, and Larry V. Hryshko. Frequencydependent regulation of cardiac Na /Ca exchanger. Am J Physiol Heart Circ Physiol 289: H1594–H1603, 2005. First published June 10, 2005; doi:10.1152/ajpheart.01094.2004.—The activity of the cardiac Na /Ca exchanger (NCX1.1) undergoes continuous modulation during the contraction-relax...

To determine whether there are abnormalities in myocyte excitation-contraction coupling and intracellular Ca2+concentration ([Ca2+]i) homeostasis in pacing-induced heart failure (PF), we measured L-type Ca2+ current ( I Ca,L) and Na+/Ca2+exchanger current ( I Na/Ca) with voltage clamp and measured intracellular Na+ concentration ([Na+]i) and [Ca2+]iwith the use of sodium-binding benzofuran isop...