Polyunsaturated fatty acids of photoreceptor membranes

Abstract Photoreceptor membrane phospholipids contain large quantities of ω3 and ω6 polyunsaturated fatty acids. Attempts to deplete these fatty acids from rod outer segments of rats by feeding a fat-free diet for 10–12 weeks were unsuccessful. Subsequent experiments showed that photoreceptor disc renewal is altered in the absence of dietary ω3 and/or ω6 fatty acids. We conclude that photoreceptor membrane renewal depends upon the availability of polyunsaturated fatty acids. Docosahexaenoic acid in photoreceptor membranes was significantly lowered by raising several generations of animals on modified fat-free diets. Electroretinographic experiments on these animals showed a decreased amplitude of the a-wave, suggesting that normal visual function is dependent upon dietary polyunsaturates.