Calcium-activated chloride channels in müller cells acutely isolated from tiger salamander retina
✍ Scribed by Nicole C. Welch; Melanie R. Lalonde; Steven Barnes; Melanie E.M. Kelly
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 281 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0894-1491
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✦ Synopsis
Abstract
Ca^2+^‐activated chloride channels were identified with whole‐cell patch‐clamp recording techniques in salamander retinal Müller cells. Cl(Ca) channels were activated by membrane depolarizations that elicited Ca^2+^ influx or the application of the Ca^2+^ ionophore, ionomycin. The Ca channel blocker, Cd^2+^, abolished the Cl(Ca) channel tail currents. Increasing the duration of the depolarizing pulse resulted in enhancement of the Cl(Ca) channel tail current. Repetitive depolarizations with rapid pulses to +20 mV produced a buildup of I~Cl(Ca)~, which reversed at 0 mV in symmetrical [Cl^−^] and at −40 mV when intracellular [Cl^−^] was reduced to 10% of the external concentration. I~Cl(Ca)~ was blocked by the Cl channel blocker niflumic acid, while niflumic acid had no effect on voltage‐gated Ca channels. These results offer the first demonstration of Cl(Ca) channels in a nonastrocytic glial cell and expand our understanding of the functional capacities of retinal glial cells. © 2005 Wiley‐Liss, Inc.