In adult cardiac cells the established mechanism of excitation-contraction coupling is by calcium-induced calcium release (CICR) mediated by L-type Ca(2+) channels. However, in neonate cardiomyocytes, a CICR modality involving reverse mode Na(+)-Ca(2+) exchanger (NCX) activity predominates. This has been hypothesized to be due, in part, to the high expression levels of NCX in the neonate heart ...

Defective excitation-contraction coupling in heart failure is generally associated with both a reduction in sarcoplasmic reticulum (SR) Ca(2+) uptake and a greater dependence on transsarcolemmal Na(+)-Ca(2+) exchange (NCX) for Ca(2+) removal. Although a relative increase in NCX is expected when SR function is impaired, few and contradictory studies have addressed whether there is an absolute in...

Gershome C, Lin E, Kashihara H, Hove-Madsen L, Tibbits GF. Colocalization of voltage-gated Na channels with the Na /Ca exchanger in rabbit cardiomyocytes during development. Am J Physiol Heart Circ Physiol 300: H300–H311, 2011. First published October 22, 2010; doi:10.1152/ajpheart.00798.2010.—Reverse-mode activity of the Na /Ca exchanger (NCX) has been previously shown to play a prominent role...

In sinoatrial node (SAN) cells, electrogenic sodium-calcium exchange (NCX) is the dominant calcium (Ca) efflux mechanism. However, the role of NCX in the generation of SAN automaticity is controversial. To investigate the contribution of NCX to pacemaking in the SAN, we performed optical voltage mapping and high-speed 2D laser scanning confocal microscopy (LSCM) of Ca dynamics in an ex vivo int...

Much less is known about the contributions of the Na(+)/Ca(2+) exchanger (NCX) and sarcoplasmic reticulum (SR) Ca(2+) pump to cell relaxation in neonatal compared with adult mammalian ventricular myocytes. Based on both biochemical and molecular studies, there is evidence of a much higher density of NCX at birth that subsequently decreases during the next 2 wk of development. It has been hypoth...

Effects of a nitroxybutylester derivative of aspirin (NCX 4215) on platelet aggregation and prostanoid synthesis were compared to the effects of aspirin. NCX 4215 was approximately seven times more potent than aspirin as an inhibitor of thrombin-induced human platelet aggregation in vitro, but did not inhibit platelet thromboxane synthesis or gastric prostaglandin synthesis. NCX 4215 released n...

BACKGROUND Sarcolemmal Na/Ca exchange (NCX) regulates cardiac Ca and contractility. NCX function during the cardiac cycle is determined by intracellular [Ca] and [Na] ([Ca]i, and [Na]i) and membrane potential (Em), which all change in human heart failure (HF). Therefore, changes in NCX function may contribute to abnormal Ca regulation in human HF. METHODS AND RESULTS We assessed the cellular ...

OBJECTIVES Expression of the cardiac Na(+)-Ca2+ exchanger (NCX) is high at birth and declines rapidly to adult levels by approximately 21 days in rabbits. The aim was to evaluate the role of thyroid hormone in regulating cardiac NCX expression. METHODS Adult New Zealand White rabbits were made hypothyroid by treatment with propylthiouracil or hyperthryoid by administration of sigma-thyroxine....

Defective excitation-contraction coupling in heart failure is generally associated with both a reduction in sarcoplasmic reticulum (SR) Ca uptake and a greater dependence on transsarcolemmal Na-Ca exchange (NCX) for Ca removal. Although a relative increase in NCX is expected when SR function is impaired, few and contradictory studies have addressed whether there is an absolute increase in NCX a...

The Na-Ca exchanger (NCX) is one of the essential regulators of Ca homeostasis in cardiomyocytes and thus an important modulator of the cardiac contractile function. The purpose of this review is to survey recent advances in cardiac NCX research, with particular emphasis on molecular and pharmacological aspects. The NCX function is thought to be regulated by a variety of cellular factors. Howev...