| Autor: |
Catalán MA; Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile.; Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile., Julio-Kalajzić F; Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile., Niemeyer MI; Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile., Cid LP; Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile., Sepúlveda FV; Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile. |
| Abstrakt: |
Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl - channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole cell recordings of ClC-2 expressed in mammalian cells are used to assay SCFA and lubiprostone effects. Using chamber measurements of ion current in mice deficient in ClC-2 or CFTR channels served to analyze the target of lubiprostone in the distal intestinal epithelium. Intracellular SCFAs had a dual action on ClC-2, partially inhibiting conduction but, importantly, facilitating the voltage activation of ClC-2. Intra- or extracellular lubiprostone had no effect on ClC-2 currents. Lubiprostone elicited a secretory current across colonic epithelia that was increased in mice deficient in ClC-2, consistent with the channel's proposed proabsorptive function, but absent from those deficient in CFTR. Whilst SCFAs might exert a physiological effect on ClC-2 as part of their known proabsorptive effect, ClC-2 plays no part in the lubiprostone intestinal effect that appears mediated by CFTR activation. |
