Na+-K+-ATPase plays a major role in regulating membrane potential and vascular tone. We analyzed the modulation by norepinephrine (NE), endothelin-1 (ET-1), and phorbol 12-myristate 13-acetate (PMA) of Na+-K+-ATPase-induced cytoplasmic free Ca2+concentration ([Ca2+]i) reduction and relaxation in isolated endothelium-denuded piglet mesenteric arteries. KCl (0.2-8.8 mM)-induced [Ca2+]ireduction a...

Normal cardiac excitation and relaxation involves a delicate balance of complex dynamic interactions between ionic currents passing through a variety of membrane channels and the cellular environment. Genetic defects, polymorphisms, therapeutic intervention or structural abnormalities can disrupt this balance and underlie severe arrhythmogenic phenotypes that lead to sudden cardiac death. Inher...

The role that Na,K-ATPase plays in Na+ and K+ antiport through the sarcolemma, in cation-homeostasis in cardiomyocytes as well as in excitation-contraction coupling and cell signalling in the myocardium is now widely recognized. It was its key importance for the cell membrane function that kept this enzyme intensively studied during the last three decades and finally brought to its discoverer t...

BLAUSTEIN, MORDECAI P. Sodium ions, calcium ions, blood pressure regulation, and hypertension: a reassessment and a hypothesis. Am. J. Physiol. 232(3): Cl65C173, 1977 or Am. J. Physiol: Cell Physiol. l(3): C1654173, 1977. -An attempt is made to elucidate the cellular mechanisms which may account for the well-documented correlation between sodium metabolism and peripheral vascular resistance. As...

Mammalian Na+/Ca2+ exchangers are members of three branches of a much larger family of transport proteins [the CaCA (Ca2+/cation antiporter) superfamily] whose main role is to provide control of Ca2+ flux across the plasma membranes or intracellular compartments. Since cytosolic levels of Ca2+ are much lower than those found extracellularly or in sequestered stores, the major function of Na+/Ca...

Hirota S, Pertens E, Janssen LJ. The reverse mode of the Na /Ca exchanger provides a source of Ca for store refilling following agonist-induced Ca mobilization. Am J Physiol Lung Cell Mol Physiol 292: L438–L447, 2007. First published October 13; doi:10.1152/ajplung.00222.2006.—Agonist-induced contraction of airway smooth muscle (ASM) can be triggered by an elevation in the intracellular Ca conc...

An attempt is made to elucidate the cellular mechanisms which may account for the well-documented correlation between sodium metabolism and peripheral vascular resistance. As a starting point, the evidence that the Na electrochemical gradient across the vascular smooth muscle cell plasma membrane (sarcolemma) plays an important role in cell calcium regulation is reviewed. Because there is signi...

BLAUSTEIN, MORDECAI P. Sodium ions, calcium ions, blood pressure regulation, and hypertension: a reassessment and a hypothesis. Am. J. Physiol. 232(3): Cl65C173, 1977 or Am. J. Physiol: Cell Physiol. l(3): C1654173, 1977. -An attempt is made to elucidate the cellular mechanisms which may account for the well-documented correlation between sodium metabolism and peripheral vascular resistance. As...

The influence of diabetes on endothelial mechanisms implicated in the response of isolated rabbit carotid arteries to 5-hydroxytryptamine (5-HT) was studied. 5-HT induced a concentration-dependent contraction that was potentiated in arteries from diabetic rabbits with respect to that in arteries from control rabbits. Endothelium removal potentiated 5-HT contractions in arteries from both contro...

Na-K-ATPase is a fundamental component of ion transport. Four α isoforms of the Na-K-ATPase catalytic α subunit are expressed in human cells. The ubiquitous Na-K-ATPase α1 was recently discovered to also mediate signal transduction through Src kinase. In contrast, α2 expression is limited to a few cell types including myocytes, where it is coupled to the Na(+)/Ca(2+) exchanger. To test whether ...