Cultured ruminal epithelial cells express a large-conductance channel permeable to chloride, bicarbonate, and acetate.
Pflugers Arch
; 457(5): 1003-22, 2009 Mar.
Article
em En
| MEDLINE
| ID: mdl-18716793
ABSTRACT
The absorption of short-chain fatty acids (SCFA) from the rumen requires efficient mechanisms for both apical uptake and basolateral extrusion. Previous studies suggest that the rumen expresses a basolateral chloride conductance that might be permeable to SCFA. In order to characterize this conductance in more detail, isolated cultured ruminal epithelial cells were studied with the patch-clamp technique, revealing a whole-cell conductance with p(Cl(-)) approximately p(NO(3) (-)) > p(HCO(3) (-)) > p(acetate(-)) > p(gluconate(-)). Currents could be blocked by diisothiocyanato-stilbene-2,2'-disulfonic acid (1 mmol l(-1) > 100 micromol l(-1)), 5-nitro-2-(3-phenylpropyl-amino)benzoic acid (50 micromol l(-1)), niflumic acid (100 micromol l(-1)), and p-chloromercuribenzoate (1 mmol l(-1)). Single-channel conductance was 350 +/- 7 pS for chloride and 142 +/- 7 pS for acetate. Open probability could be fitted with a three-state gating model. We propose a role for this channel in mediating the permeation of chloride, bicarbonate, and acetate across the basolateral membrane of the ruminal epithelium.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Rúmen
/
Bicarbonatos
/
Ativação do Canal Iônico
/
Cloretos
/
Acetatos
Limite:
Animals
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article