Purchase this article with an account.
M. J. Goodyear, S. G. Crewther, M. Murphy Edwards, B. M. Junghans, A. Hazi, D. P. Crewther; A Role for Aquaporin-4 (AQP4) Channels and Inward-Rectifying Potassium Channels (Kir4.1) During Refractive Compensation to Optical Defocus. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5938.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Inwardly rectifying potassium channels Kir4.1 are typically found to be co-localised with AQP4 channels in mammalian retina and have been postulated to influence the osmotic environment leading to rapid cellular water movements during light-dark transduction. Thus as we have previously shown (ARVO 2005 and 2006) that AQP4 expression is associated with the development of myopia in chick we have now examined the pattern of expression of Kir4.1 and AQP4 during the induction of myopia and hyperopia.
Sixty chickens were raised from Day 5 for various durations (t=24, 48, 72, 96 or 120 hours) wearing either no lenses or monocular +/-10D spectacle goggles. Changes in refractive state and measures of ocular growth were determined using retinoscopy and A-scan ultrasonography prior to sacrifice. Eyes were cryosectioned and prepared for immunohistochemistry using anti-Kir4.1 and anti-AQP4 antibodies.
Refractive compensation and ocular growth occurred in the expected sign dependent manner. Immunohistochemistry revealed differential expression between Kir4.1 and AQP4 in the inner plexiform layer, ganglion cell layer and nerve fiber layer in a pattern consistent with the morphology of the Mueller cell. Differential expression of AQP4 and Kir4.1 was apparent within 24 hours of the initiation of optical defocus, was sign related, and reduced over time as refractive compensation was achieved.
These results indicate that Kir4.1 and AQP4 channels on Mueller cells are both associated with the morphological changes seen during the induction of myopia and hyperopia, though the sites of major expression of these two channel proteins is not identical.
This PDF is available to Subscribers Only