Expression of isoforms of the Na(+)/H(+) exchanger in M-1 mouse cortical collecting duct cells.
Na(+)/H(+) exchanger (NHE) proteins perform a variety of functions in the kidney and are differentially distributed among nephron segments. The purpose of this study was to identify NHE isoforms in murine M-1 cells as a model of cortical collecting duct principal cells. It was found that mRNAs corresponding to NHE1, NHE2, and NHE4 are expressed in M-1 cells. NHE-dependent regulation of intracellular pH (pH(i)) was investigated in the absence of extracellular HCO. Application of a 20 mM NH(4)Cl pulse resulted in a reversible intracellular acidification from which recovery was partially inhibited by application of 1 mM amiloride to either the apical or the basolateral membranes and was abolished when amiloride was applied to both sides of the monolayers, which suggests that NHEs are expressed in both the apical and the basolateral cell membranes of M-1 cells. The purinergic agonists ATP and benzoylbenzoyl-ATP caused a reduction of pH(i) when applied to the apical membrane, which suggests pH(i) may be influenced by extracellular nucleotides in the luminal fluid of the cortical collecting duct.
Hill
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C
Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
Giesberts
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AN
White
S J
SJ
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D007672:Kidney Cortex / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000378:metabolism*; D051379:Mice; D009711:Nucleotides / Q000494:pharmacology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000096:biosynthesis* / Q000378:metabolism
D009711:Nucleotides; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; C513111:Slc9a2 protein, mouse; C489906:Slc9a4 protein, mouse; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1; D012964:Sodium