IDIM   12530
INSTITUTO DE INVESTIGACIONES MEDICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Role of the intracellular sodium concentration on the effect of hypotonic shock on the epithelial sodium channel (ENaC).
Autor/es:
GALIZIA L; MARINO GI; PALMA AG; KOTSIAS BA
Lugar:
Salto
Reunión:
Congreso; XLII Reunión de la Sociedad argentina de Biofísica y Sociedad Uruguaya de Biociencias; 2015
Institución organizadora:
Sociedad Argentina de Biofísica
Resumen:
The regulation of the epithelial Na+ channel (ENaC) during cell volume increase is relevant in cellular processes involving osmotic challenges. ENaC function is affected by changes of the intracellular sodium concentration. Its sensitivity to hypotonic-induced swelling was investigated in the Xenopus oocyte expression system with the injection of the three subunits of the mouse ENaC (mENaC) [1]. We used the voltage clamp technique to measure the amiloride-sensitive Na+ currents (INa(amil)) in order to study the role of intracellular sodium on the ENaC regulation mediated by hyposmotic challenges. ENaC-injected oocytes different intracellular sodium conditions, showed a significative reduction of INa(amil) inward currents from 10 mM to 40 mM. However inactivation of the currents at hyperpolarized pulses increases in that range. Oocytes expressing a DEG mutant of the β-ENaC subunit (β-S518K), which produce an open probability equal to 1 showed a reduced INa(amil) hypotonic mediated inhibitory response in both conditions of intracellular sodium concentration. Based on these results, we suggest that hypotonicity-dependent ENaC inhibition, due to open probability changes is mediated by an intracellular sodium dependent mechanism, probably trough a voltage dependent inactivation effectReferences1 Galizia et al J Membr Biol. 2013. 246 P 949.