Vacuolar-type H+-ATPase-mediated proton transport in the rat parietal cell.
Pflugers Arch
; 463(3): 419-27, 2012 Mar.
Article
en En
| MEDLINE
| ID: mdl-22146938
ABSTRACT
The vacuolar-type H-ATPase (V-ATPase) plays an important role in the active acidification of intracellular organelles. In certain specialized cells, such as the renal intercalated cell, apical V-ATPase can also function as a proton secretion pathway. In the parietal cells of the stomach, it has been thought that acid secretion is controlled solely via the H,K-ATPase. However, recent observations suggest that functional V-ATPase is necessary for acid secretion to take place. This study aimed to investigate and characterize the role of V-ATPase in parietal cell proton transport. Individual rat gastric glands were incubated with the pH-sensitive dye (BCECF) to monitor changes in intracellular pH in real time. Parietal cell V-ATPase activity was measured by quantifying the rate of intracellular alkalinization (ΔpH/minute) following an acid load, while excluding the contribution of non-V-ATPase proton transport mechanisms through pharmacological inhibition or ion substitution. Expression of V-ATPase was confirmed by immunohistochemistry. We observed concanamycin A-sensitive V-ATPase activity in rat parietal cells following intracellular acidification and H,K-ATPase inhibition. Furthermore, V-ATPase-mediated proton transport could be abolished by inhibiting trafficking mechanisms with paclitaxel and by stimulating H,K-ATPase with acid secretagogues. Our results propose that parietal cells contain a functional V-ATPase that can be mobilized using a microtubule network. V-ATPase may function as an auxiliary acid secretion or proton-buffering pathway in parietal cells, which is inactive during H,K-ATPase activity. Our findings may have important implications for patients experiencing acid breakthrough under proton pump inhibitor therapy.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Células Parietales Gástricas
/
ATPasas de Translocación de Protón Vacuolares
Límite:
Animals
Idioma:
En
Revista:
Pflugers Arch
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos