Premium
The role of Cl‐ channels in ion transport across the apical and basolateral sides of the mouse retinal pigment epithelium
Author(s) -
SKARPHEDINSDOTTIR S,
EYSTEINSSON T,
ARNASON S
Publication year - 2014
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2014.f010.x
Subject(s) - retinal pigment epithelium , apical membrane , chemistry , channel blocker , epithelial polarity , ion transporter , epithelium , transepithelial potential difference , biophysics , anatomy , retinal , medicine , endocrinology , biology , biochemistry , pathology , membrane , calcium
Purpose The retinal pigment epithelium (RPE) is important in transporting water from the subretinal space to the choroid of the eye. The water transport across the RPE is supposed to be mediated by Cl‐ channels situated at the basolateral side of the RPE tissue. The purpose of this study was to assess the function of Cl‐ channels at the apical and basolateral side of mouse RPE. Methods RPE of healthy mice (C57BL/6J) was mounted in Ussing chambers. The short‐circuit current (Isc) was measured in μAmp/cm2. The non‐specific Cl‐ channel blocker NPPB (4 mM) was applied to both sides. The CFTR blocker CFTRinh‐172 (0.8 mM) was added to the apical side. The Ca++ dependent Cl‐ channel blocker CaCCinh‐A01 (1.15 mM ) was added to the apical side. Each dose of the blockers was tested for 30 minutes. The results are presented as mean ± SEM, n = 6 in all experiments. Results NPPB (4 mM) on the basolateral side produced no significant change (p = 0.36; 30 min), but 4 mM NPPB on the apical side reversed the Isc (μAmp/cm2) from ‐4,8 ± 5,9 to +19.9 ± 7,3 (p = 0.004) at 5 min which stabilised at +2.9 ± 4,9 (p = 0.03) at 30 min. CFTRinh‐172 (0.8 mM) caused a transient increase, ‐13 ± 3,5 to ‐15,1 ± 3,3 (p = 0.02) at 5 min. CaCCinh‐A01 (1.15 mM) reversed the Isc from ‐10,6 ± 2,1 to +5,5 ± 3,9 (p = 0.0002) at 10 min, which stabilized at ‐0.10 ± 3,0 (p = 0.002) at 30 min. Conclusion The results indicate that Cl‐ channels are situated on the apical side of the RPE and drive a part of the ion transport across the mouse RPE. The channels may play a lesser role in ion transport across the basolateral side.