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Stimulation of purinergic receptors inhibits amiloride-sensitive Na+ transport in epithelial tissues by an unknown mechanism. Because previous studies excluded the role of intracellular Ca2+ or protein kinase C, we examined whether purinergic regulation of Na+ absorption occurs via hydrolysis of phospholipid such as phosphatidylinositol-bisphosphates(More)
Cystic fibrosis (CF) airway cells, besides their well-known defect in cAMP-dependent Cl- conductance, are characterized by an enhanced Na+ conductance. In this study we have examined the Na+ conductance in human respiratory tract by measuring transepithelial voltage and resistance (Vte, Rte) and by assessing membrane voltages (Vm) of freshly isolated airway(More)
Activation of the CFTR Cl- channel inhibits epithelial Na+ channels (ENaC), according to studies on epithelial cells and overexpressing recombinant cells. Here we demonstrate that ENaC is inhibited during stimulation of the cystic fibrosis transmembrance conductance regulator (CFTR) in Xenopus oocytes, independent of the experimental set-up and the(More)
Cystic fibrosis is characterized by an impaired cyclic adenosine 3,5-monophosphate (cAMP) activated Cl- conductance in parallel with an enhanced amiloride sensitive Na+ conductance (ENaC) of the respiratory epithelium. Very recently, acute downregulation of ENaC by the cystic fibrosis transmembrane conductance regulator (CFTR) was demonstrated in several(More)
PURPOSE Voltage-gated Kv potassium channels, like ether a go-go (EAG) channels, have been recognized for their oncogenic potential in breast cancer and other malignant tumors. EXPERIMENTAL DESIGN We examined the molecular and functional expression of Kv channels in human colonic cancers and colon of mice treated with the chemical carcinogens(More)
Rotavirus infection is the most frequent cause for severe diarrhea in infants, killing more than 600,000 every year. The nonstructural protein NSP4 acts as a rotavirus enterotoxin, inducing secretory diarrhea without any structural organ damage. Electrolyte transport was assessed in the colonic epithelium from pups and adult mice using Ussing chamber(More)
Cystic fibrosis transmembrane conductance regulator (CFTR) is an epithelial Cl– channel expressed in luminal membranes of secretory and reabsorptive epithelia. CFTR plays a predominant role in both cAMP- and Ca2+-activated secretion of electrolytes. Although Ca2+-dependent Cl– channels exist independent of CFTR in the airway epithelium, their physiological(More)
The cystic-fibrosis transmembrane conductance regulator (CFTR) functions as a cAMP-regulated Cl- channel and as a regulator of other membrane conductances. cAMP-dependent activation of CFTR inhibits epithelial Na+ channels (ENaC). The specificity of interaction between CFTR and ENaC was examined by coexpression of ENaC and ATP-binding cassette (ABC)(More)
Abstract Both stimulation of purinergic receptors by ATP and activation of the cystic fibrosis transmembrane conductance regulator (CFTR) inhibit amiloride-sensitive Na+ transport and activate Cl− secretion. These changes in ion transport may well affect cell volume. We therefore examined whether cell shrinkage or cell swelling do affect amiloride-sensitive(More)
TMEM16A (anoctamin 1, Ano1), a member of a family of 10 homologous proteins, has been shown to form an essential component of Ca(2+)-activated Cl(-) channels. TMEM16A-null mice exhibit severe defects in epithelial transport along with tracheomalacia and death within 1 mo after birth. Despite its outstanding physiological significance, the mechanisms for(More)