A proton-translocating H+-ATPase is involved in C6 glial pH regulation.
Biochim Biophys Acta
; 1372(1): 28-36, 1998 Jun 24.
Article
en En
| MEDLINE
| ID: mdl-9651471
ABSTRACT
Glial cells extrude acid equivalents to maintain pHi. Although four mechanisms have been described so far, pHi-control under physiological conditions is still not sufficiently explained. We therefore investigated whether a H+-translocating ATPase is involved in glial pHi homeostasis using an established glial cell line (C6 glioma). In the absence of bicarbonate, the inhibition of H+-ATPases by NEM led to a pHi decrease. The application of a more specific inhibitor (NBD-Cl) showed that the H+-ATPase involved is of the vacuolar type. Inhibition went along with delayed cell swelling. Together with the fact that glial acidification was far more pronounced in Na+-free media, this may serve as evidence for a secondary activation of Na+/H+-exchange once an activation setpoint is reached, which in turn causes secondary swelling from Na+-uptake. Stimulation of Na+/H+-exchange by PMA can increase the setpoint. pHi-recovery after an acid load was blocked by the inhibition of v-type H+-ATPase, if pHi did not reach 6.6 during the acid load. The inhibition of Na+/H+-exchange by amiloride inhibited recovery only if acidification was below the threshold. Finally, in bicarbonate-free media a v-type H+-ATPase contributes to pH-regulation in glial cells, especially during pH-homeostasis at physiological conditions, while Na+/H+-exchange gains significance during severe acid loads.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ATPasas de Translocación de Protón
/
Glioma
Límite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
1998
Tipo del documento:
Article
País de afiliación:
Alemania