These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Coupled Na+/H+ exchange in rat parotid basolateral membrane vesicles.
    Author: Manganel M, Turner RJ.
    Journal: J Membr Biol; 1988 Jun; 102(3):247-54. PubMed ID: 2845092.
    Abstract:
    pH gradient-dependent sodium transport in highly purified rat parotid basolateral membrane vesicles was studied under voltage-clamped conditions. In the presence of an outwardly directed H+ gradient (pHin = 6.0, pHout = 8.0) 22Na uptake was approximately ten times greater than uptake measured at pH equilibrium (pHin = pHout = 6.0). More than 90% of this sodium flux was inhibited by the potassium-sparing diuretic drug amiloride (K1 = 1.6 microM) while the transport inhibitors furosemide (1 mM), bumetanide (1 mM), SITS (0.5 mM) and DIDS (0.1 mM) were without effect. This transport activity copurified with the basolateral membrane marker K+-stimulated p-nitrophenyl phosphatase. In addition, 22Na uptake into the vesicles could be driven against a concentration gradient by an outwardly directed H+ gradient. pH gradient-dependent sodium flux exhibited a simple Michaelis-Menten-type dependence on sodium concentration consistent with the existence of a single transport system with KM = 8.0 mM at 23 degrees C. A component of pH gradient-dependent, amiloride-sensitive sodium flux was also observed in rabbit parotid basolateral membrane vesicles. These results provide strong evidence for the existence of a Na+/H+ antiport in rat and rabbit parotid acinar basolateral membranes and extend earlier less direct studies which suggested that such a transporter was present in salivary acinar cells and might play a significant role in salivary fluid secretion.
    [Abstract] [Full Text] [Related] [New Search]