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Recent experiments involving the measurement of intracellular activities in Na+ and Ca2+; functional studies; descriptions of the Na+ and Ca2+ fluxes from intact cardiac tissue; studies of isolated cardiac sarcolemmal vesicles, isolated sarcoplasmic reticulum (SR) vesicles, and isolated mitochondria; and investigations of the behavior of cardiac contractile(More)
A method for mounting and rapidly perfusing small ventricular trabeculae (diameter around 250 micron) from either ferret or guinea-pig is described. Tension, membrane potential (Em) and intracellular Na activity (aiNa) were measured. aiNa was measured using Na-sensitive micro-electrodes. At room temperature (22-26 degrees C), [Na]o 155 mmol/l and [Ca]o 5.4(More)
OBJECTIVE The aim was to investigate the effects of raising intracellular taurine on the intracellular sodium activity (aNa1) in isolated guinea pig ventricular myocytes, and the effect of procedures that raise intracellular sodium on taurine concentration in the perfused guinea pig ventricular tissue. METHODS Taurine was introduced into the sarcoplasm of(More)
1. Trabeculae isolated from ferret heart and from other mammalian hearts have been mounted in a way that enables the tension generated to be measured while the composition of the bathing fluid is rapidly altered.2. Application of caffeine to these trabeculae initiates a rapid transient contracture and depresses the strength of regularly evoked heart(More)
OBJECTIVE Although it is widely accepted that the hypercontraction provoked by the influx of Ca2+ on return to normal Tyrode solution after a period of Ca2+ depletion (the calcium paradox) contributes to the damage to the cell membrane, it remains possible that the Ca2+ overload activates intracellular enzymes that are important in the initial degradation(More)
1. The force of contraction and the membrane potentials have been measured from preparations of frog heart, with methods that also allow the rapid exchange of the extracellular fluid.2. In regularly beating preparations, caffeine induces only weak contractures at temperatures above 15 degrees C, but it does cause a marked potentiation of the twitch(More)
1. Single Na+-activated K+ channels (K(Na)) were investigated by means of the inside-out patch clamp technique in ventricular myocytes isolated from the guinea-pig heart. 2. Na+-activated K+ channels were observed at very low density (< 9% of patches). In symmetrical (60/60 mM) K+ solutions, K(Na) channels had a mean slope conductance of 75 pS and in(More)
DISCLAIMER This paper was prepared by a California Energy Commission staff person. It does not necessarily represent the views of the Energy Commission or the State of California. The Energy Commission, the State of California, its employees, contractors and subcontractors make no warrant, express or implied, and assume no legal liability for the(More)