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From the Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
PURPOSE. Diet-induced deficiencies in Omega-3 (
-3) fatty acids are well known to alter photoreceptor function. In this study, the broader functional changes in a diversity of retinal neurons were considered.
METHODS. Sprague-Dawley dams were fed either
-3-sufficient (
-3+, n = 21) or -deficient (
-3–, n = 19) diets 5 weeks before conception, with the pups continued on the mothers diet. After 20 weeks of age, electroretinograms (ERGs) were recorded by using protocols that isolate separate cellular generators, including; photoreceptors (PIII), ON-bipolar cells (PII), and ganglion/amacrine cells (STR). At the brightest energies, rod and cone responses were isolated with a paired-flash paradigm. Retinal tissue (
-3+, n = 5;
-3–, n = 5) was harvested at 23 weeks of age for fatty acid assays with thin layer and gas liquid chromatography.
RESULTS. Omega-3 deficiency caused a 48.6% decrease in total retinal docosahexaenoic acid (DHA). This change induced significant amplitude decreases only in the rod PII (–8.2%) and positive (p)STR components (–27.4%), with widespread delays in all signals (PIII 5.7%, PII 13.6%, pSTR 7.6%, and negative [n]STR 8.3%). Omega-3 deficiency exerted its greatest effects on signals originating in the inner retina (pSTR).
CONCLUSIONS. Increasing dietary
-3 has beneficial effects across the retina, with the greatest improvement occurring in ganglion cell function.
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