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. Author manuscript; available in PMC: 2012 Apr 4.
Published in final edited form as: Prog Retin Eye Res. 2008 May 22;27(4):420–433. doi: 10.1016/j.preteyeres.2008.04.001

Figure 5. Kir4.1 and AQP4 are expressed in retinal Müller cells but are functionally independent.

Figure 5

A. (left panel) Colocalization of Kir4.1 (green) and AQP4 (red) in isolated Müller cells from wildtype (+/+, top) and AQP4 null (−/−, bottom) mice, with nuclei stained with DAPI (blue). A, apical end; S, soma; EF, endfoot. (two right panels) Retinal sections from mice. ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer; ILM, inner limiting membrane. B. Spatially resolved Kir4.1 K+ conductance in Müller cells. (left) Phase-contrast micrograph showing Müller cell with soma puncture and K+ injection micropipette positioned where indicated by white arrows. Endfoot at the top and apical end at the bottom. (right) Representative whole-cell current recordings (voltage −80 mV) before and following pulsed injections of 50 mM K+ solution for wildtype (left) and AQP4 null (right) Müller cells. C. Mean current-voltage (I–V) curves of whole-cell currents in Müller cells. D. Single-channel patch-clamp of Kir4.1 K+ channels with unitary current-voltage data. Inset shows representative single-channel current traces from cell-attached membrane patches with 145 mM K+ in the pipette at −60 mV. Adapted from Ruiz-Ederra et al. (2007).