Evidence for ammonium conductance in a mouse thick ascending limb cell line.
Physiol Rep
; 5(16)2017 Aug.
Article
en En
| MEDLINE
| ID: mdl-28830978
In this study, we examined an ammonium conductance in the mouse thick ascending limb cell line ST-1. Whole cell patch clamp was performed to measure currents evoked by NH4Cl in the presence of BaCl2, tetraethylammonium, and BAPTA Application of 20 mmol/L NH4Cl induced an inward current (-272 ± 79 pA, n = 9). In current-voltage (I-V) relationships, NH4Cl application caused the I-V curve to shift down in an inward direction. The difference in current before and after NH4Cl application, which corresponds to the current evoked by NH4Cl, was progressively larger at more negative potentials. The reversal potential for NH4Cl was +15 mV, higher than the equilibrium potential for chloride, indicating that the current should be due to NH4+ We then injected ST-1 poly(A) RNA into Xenopus oocytes and performed two-electrode voltage clamp. NH4Cl application in the presence of BaCl2 caused the I-V curve to be steeper. The NH4+ current was retained at pH 6.4, where endogenous oocyte current was abolished. The NH4+ current was unaffected by 10 µmol/L amiloride but abolished after incubation in Na+-free media. These results demonstrate that the renal cell line ST-1 produces an NH4+ conductance.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Potenciales de Acción
/
Compuestos de Amonio
/
Asa de la Nefrona
Límite:
Animals
Idioma:
En
Revista:
Physiol Rep
Año:
2017
Tipo del documento:
Article
País de afiliación:
Georgia
Pais de publicación:
Estados Unidos