Transporte electrogénico en el colon de ratas privadas de sodio
Dietary sodium deprivation stimulates aldosterone secretion. In the rat colon, high aldosterone levels increases Na+ absorption but also switches the mechanism of Na+ absorption from electroneutral to electrogenic. Such electrogenic transport may be suppressed by either epithelial Na+ channel block...
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| Publicado en: | Revista Médica Universitaria |
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| Autores principales: | , , , , |
| Materias: | |
| Acceso en línea: | https://bdigital.uncu.edu.ar/fichas.php?idobjeto=6412 |
| Sumario: | Dietary sodium deprivation stimulates aldosterone secretion. In the rat colon, high aldosterone levels increases Na+ absorption but also switches the mechanism of Na+
absorption from electroneutral to electrogenic. Such electrogenic transport may be suppressed by either epithelial Na+ channel blockade at the apical membrane or
Na, K-ATPase inhibition at the basolateral membrane. Electrogenic Na+ absorption is tightly coupled to aerobic metabolism, but it is not known whether epithelial Na+
channel blockade and Na, KATPase inhibition cause the same degree of reduction in epithelial oxygen consumption. Distal colon isolated mucosa preparations were
obtained from rats fed with a low sodium diet for 10 days. Short-circuit current and oxygen consumption were simultaneously measured in baseline condition and after either blocking epithelial Na+ channels with amiloride (n=12) or the Na, KATPase
with ouabain (n=12). Both treatments reduced short-circuit current to the same degree, but the reduction in oxygen consumption was larger with ouabain (p<0.03).
The difference may be due to the fact that Na, K-ATPase has other functions besides transepithelial Na+ transport, which are suppressed by ouabain but not by amiloride. |
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