Expression and regulation of chloride channels in neonatal rat cardiomyocytes.
Using an 125I- efflux assay, we have studied the expression of various types of chloride channels in isolated neonatal rat cardiomyocytes. Three different classes of anion conductances were distinguished: (1) a Ca(2+)-sensitive Cl- conductance, triggered upon stimulation of the cells with endothelin-1 or Ca(2+)-ionophore; (2) a cAMP/protein kinase A-operated Cl- conductance, activated by addition of forskolin. This anion channel could be identified as the Cystic Fibrosis Transmembrane conductance Regulator (CFTR-CI- channel) by Western blotting as well as by its enhanced activity in cultures pretreated with the tyrosine kinase inhibitor genistein; (3) a distinct class of cell volume-regulated Cl- channels, potentiated in the presence of endothelin-1 or the phosphotyrosine phosphatase inhibitor pervanadate. The potential role of each class of Cl- channels in the generation and/or modulation of action potentials as well as in maintaining cell volume is discussed.
Tilly
B C
BC
Department of Biochemistry, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, The Netherlands.
Bezstarosti
K
K
Boomaars
W E
WE
Marino
C R
CR
Lamers
J M
JM
de Jonge
H R
HR
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D018118:Chloride Channels / Q000096:biosynthesis* / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000096:biosynthesis / Q000502:physiology; D016232:Endothelins / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D019833:Genistein; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006982:Hypertonic Solutions; D007038:Hypotonic Solutions; D007454:Iodides / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007529:Isoflavones / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D014638:Vanadates / Q000494:pharmacology
D018118:Chloride Channels; D016232:Endothelins; D004791:Enzyme Inhibitors; D006982:Hypertonic Solutions; D007038:Hypotonic Solutions; D007454:Iodides; D007457:Iodine Radioisotopes; D007529:Isoflavones; C076715:pervanadate; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005576:Colforsin; D000001:Calcimycin; D014638:Vanadates; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine