The Na(+) current component I(Ca(TTX)) is functionally distinct from the main body of Na(+) current, I(Na). It was proposed that I(Ca(TTX)) channels are I(Na) channels that were altered by bathing media containing Ca(2+), but no, or very little, Na(+). It is known that Na(+)-free conditions are not required to demonstrate I(Ca(TTX).) We show here that Ca(2+) is also not required. Whole-cell, te...

Calcium-45 was injected into single giant barnacle muscle fibers, and the rate of efflux was measured under a variety of conditions. The rate constant (k) for (45)Ca efflux into standard seawater averaged 17 x 10(-4) min(-1) which corresponds to an efflux of about 1-2 pmol/cm(2).s. Removal of external Ca (Ca(o)) reduced the efflux by 50%. In most fibers about 40% of the (45)Ca efflux into Ca-fr...

Ca(2+) is a central player in the excitation-contraction coupling of cardiac myocytes, the process that enables the heart to contract and relax. Mishandling of Ca(2+) is a central cause of both contractile dysfunction and arrhythmias in pathophysiological conditions such as heart failure (HF). Upon electrical excitation, Ca(2+) enters the myocytes via voltage-gated Ca(2+) channels and induces f...

Na-Ca exchange is proposed to be an important regulator of myoplasmic intracellular Ca concentration ([Ca]|) and contraction in vascular smooth muscle. We investigated the role of Na-Ca exchange in regulating [Ca], in swine carotid arterial tissues that were loaded with aequorin to allow simultaneous measurement of [Ca], and force. Reversal of Na-Ca exchange, by reduction of extracellular Na co...

Na+- and CA2+-sensitive microelectrodes were used to measure intracellular Na+ and Ca2+ activities (alpha iCa) of sheep ventricular muscle and Purkinje strands to study the interrelationship between Na+ and Ca2+ electrochemical gradients (delta muNa and delta muCa) under various conditions. In ventricular muscle, alpha iNa was 6.4 +/- 1.2 mM and alpha iCa was 87 +/- 20 nM ([Ca/+] = 272 nM). A g...

Na-Ca exchange is proposed to be an important regulator of myoplasmic intracellular Ca concentration ([Ca]|) and contraction in vascular smooth muscle. We investigated the role of Na-Ca exchange in regulating [Ca], in swine carotid arterial tissues that were loaded with aequorin to allow simultaneous measurement of [Ca], and force. Reversal of Na-Ca exchange, by reduction of extracellular Na co...

Stimulus-dependent elevation of intracellular Ca(2+) ([Ca(2+)](i)) affects the expression of numerous genes--a phenomenon known as excitation-transcription coupling. Recently, we found that increases in [Na(+)](i) trigger c-Fos expression via a novel Ca(2+) (i)-independent pathway. In the present study, we identified ubiquitous and tissue-specific [Na(+)](i)/[K(+)](i)-sensitive transcriptomes b...

background: the present study investigated the effect of the middle east dust storm episodes on the concentration and composition of pm 10 during april to september 2013 in sanandaj city, western iran. methods: sampling was once every six days, and on dusty days using an omni air sampler. the pm 10 sample was collected on polytetrafluoroethylene filters. average of 24 h values of pm 10 mass con...

transport by the human Na ϩ /Ca 2ϩ exchanger expressed in Sf 9 cells. Am. block of the Na ϩ /Ca 2ϩ exchanger was examined in Sf 9 cells expressing the human heart Na ϩ /Ca 2ϩ exchanger (NCX1-NACA1). As predicted from the reported actions of Ni 2ϩ , its application reduced extracellular Na ϩ-dependent changes in intracellular Ca 2ϩ concentration (measured by fluo 3 fluores-cence changes). Howeve...

screening methods that are effective in the early stage of growth will potentially provide the largest quantity of breeding material. although various screening methods under greenhouse have been proposed, potential effective approaches must be described a good correlation with results under field conditions. this study was aimed to assess the correlations between traits obtained from four salt...