Extracellular Na(+) levels regulate formation and activity of the NaX/alpha1-Na(+)/K(+)-ATPase complex in neuronal cells.
Front Cell Neurosci
; 8: 413, 2014.
Article
em En
| MEDLINE
| ID: mdl-25538563
ABSTRACT
MnPO neurons play a critical role in hydromineral homeostasis regulation by acting as sensors of extracellular sodium concentration ([Na(+)]out). The mechanism underlying Na(+)-sensing involves Na(+)-flow through the NaX channel, directly regulated by the Na(+)/K(+)-ATPase α1-isoform which controls Na(+)-influx by modulating channel permeability. Together, these two partners form a complex involved in the regulation of intracellular sodium ([Na(+)]in). Here we aim to determine whether environmental changes in Na(+) could actively modulate the NaX/Na(+)/K(+)-ATPase complex activity. We investigated the complex activity using patch-clamp recordings from rat MnPO neurons and Neuro2a cells. When the rats were fed with a high-salt-diet, or the [Na(+)] in the culture medium was increased, the activity of the complex was up-regulated. In contrast, drop in environmental [Na(+)] decreased the activity of the complex. Interestingly under hypernatremic condition, the colocalization rate and protein level of both partners were up-regulated. Under hyponatremic condition, only NaX protein expression was increased and the level of NaX/Na(+)/K(+)-ATPase remained unaltered. This unbalance between NaX and Na(+)/K(+)-ATPase pump proportion would induce a bigger portion of Na(+)/K(+)-ATPase-control-free NaX channel. Thus, we suggest that hypernatremic environment increases NaX/Na(+)/K(+)-ATPase α1-isoform activity by increasing the number of both partners and their colocalization rate, whereas hyponatremic environment down-regulates complex activity via a decrease in the relative number of NaX channels controlled by the pump.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Front Cell Neurosci
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Canadá