Тип публикации: статья из журнала
Год издания: 2003
Идентификатор DOI: 10.1007/s00232-002-1067-8
Ключевые слова: Cftr, ENaC, Xenopus oocytes, Mouse trachea, cystic fibrosis, Cell swelling, osmotic stress, UTP, Atp, purinergic receptors, Epithelial transport
Аннотация: 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 Na+ transport in epithelial tissues or Xenopus oocytes and whether osmotic stress interferes with regulation of Na+ transport by ATP or CFTR. Stimulation of purinergic receptors by ATP/UTP or activation of CFTR by IBMX and forskolin inhibited amiloride-sensitive transport in mouse trachea and colon, respectively, by a mechanism that was Cl- dependent. When exposed to a hypertonic but not hypotonic bath solution, amiloride-sensitive Na+ transport was inhibited in mouse trachea and colon, independent of the extracellular Cl- concentration. Both inhibition of Na+ transport by hypertonic bath solution and ATP were additive. When coexpressed in Xenopus oocytes, activation of CFTR by IBMX and forskolin inhibited the epithelial Na+ channel (ENaC) in a Cl-dependent fashion. However, both hypertonic and hypotonic bath solutions showed only minor effects on amiloride-sensitive conductance, independent of the bath Cl- concentration. Moreover, CFTR-induced inhibition of ENaC could be detected in oocytes even after exposure to hypertonic or hypotonic bath solutions. We conclude that amiloride-sensitive Na+ absorption in mouse airways and colon is inhibited by cell shrinkage by a mechanism that does not interfere with purinergic and CFTR-mediated inhibition of ENaC.
Журнал: The Journal of Membrane Biology
Выпуск журнала: Т. 192, № 2
Номера страниц: 101-110
ISSN журнала: 00222631
Издатель: Springer-Verlag New York