Abstract
Docosahexaenoic acid (DHA), a long chain fatty acid of n-3 series, is highly enriched in the membrane phospholipids of the retina as well as brain and neuronal tissues. Loss of DHA because of n-3 deficiency is associated with visual deficits as observed in animal and human infants study. How is DHA related to retinal structure and function? Recent research provided the evidence that rod outer segment (ROS) from n-3 fatty acid-deficient rats showed desensitization of the visual signaling steps in a G protein-coupled receptor signal transduction. ROS membranes from n-3 deficient rats exhibited a higher degree of phospholipids acyl chain order. Thus, DHA may operate in signaling cascades to enhance activation of membrane-bound receptors and subsequent signaling events by optimizing biophysical membrane properties. DHA may also be involved in rhodopsin regeneration. On the other hand, DHA-derived neuroprotective mediator was isolated from human retinal pigment epithelial cells and identified as 10, 17S-docosatriene named neuroprotectin Dl. In conclusion, there is consistent evidence to suggest that n-3 fatty acids may act in a pivotal role for the visual signaling and a protective role against pathology of retina such as retinitis pigmentosa.
