Purchase this article with an account.
Marc H. Levin, A. S. Verkman; CFTR-Regulated Chloride Transport at the Ocular Surface in Living Mice Measured by Potential Differences. Invest. Ophthalmol. Vis. Sci. 2005;46(4):1428-1434. doi: 10.1167/iovs.04-1314.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
purpose. To define the role of the cystic fibrosis transmembrane conductance regulator (CFTR) in Cl− secretion at the mouse ocular surface in vivo.
methods. Open-circuit potential differences (PDs) across the fluid-bathed ocular surface were measured in anesthetized wild-type and cystic fibrosis (CF) mice in response to Cl− ion substitution and transport agonists and inhibitors.
results. Basal ocular surface PD was −23 ± 1 mV (SE; 20 wild-type mice), depolarizing to −16 ± 2 mV after amiloride, then hyperpolarizing to −34 ± 3 mV after low Cl−. CFTR activation by forskolin or a selective activator caused further sustained hyperpolarization to −50 to −60 mV. UTP produced a comparable but transient hyperpolarization. The CFTR inhibitors CFTRinh-172 and GlyH-101 largely reversed agonist- but not low Cl−-induced hyperpolarizations. PD in CF mice hyperpolarized by 2.1 mV after low Cl− and was insensitive to CFTR activators or inhibitors.
conclusions. CFTR provides a major pathway for mouse ocular surface Cl− secretion, suggesting the application of CFTR activators as therapy for dry eye. Amiloride-sensitive Na+ transporters facilitate Na+ absorption. PD measurements provide a robust and reproducible means of assessing ocular surface ion transporting mechanisms.
This PDF is available to Subscribers Only