**4. My participation in studies with photoreceptor**

I started researching lipids almost six decades ago. My main interest was focused on the study of fatty acids. From 1990 up to now, our laboratory has been interested in the lipid peroxidation of biological membranes from various tissues and different species as well as liposomes prepared with phospholipids rich in PUFAs, as a consequence and considering that the retina is a tissue with enormous amounts of polyunsaturated fatty acids, our studies focused on the lipid peroxidation of photoreceptor membranes. In our first study, it was investigated if soluble-binding proteins for fatty acids (FABPs) present in neural retina show protection from in vitro lipoperoxidation of rod outer segment membranes (ROS). [1] Also we studied the effect of alpha-tocopherol, all-trans retinol, and retinyl palmitate on the nonenzymatic lipid peroxidation of rod outer segments [2].

Retina is highly susceptible to oxidative damage due to its high content of polyunsaturated fatty acids (PUFAs), mainly docosahexaenoic acid (22:6 n3). Lipid peroxidation process is thought to be involved in many physiological and pathological events. Many model membranes can be used to learn more about issues that cannot be studied in biological membranes. Sonicated liposomes (SL) and non-sonicated liposomes (NSL) prepared with lipids isolated from bovine retina and characterized

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*Prologue: My Experience with Photoreceptors - The Peroxidation of Lipids*

liposomes made of retinal lipids [8]; for reviews, see [9, 10].

**5. General remarks, conclusions, and perspectives**

damage research will dominate in the future.

**Acknowledgements**

HU/PA03-BI/008.

by dynamic light-scattering were submitted to lipid peroxidation, under air atmosphere at 22°C, with Fe(2+) or Fe(3+) as initiator, in different aqueous media. We verified that peroxidation of liposomes made of retinal lipids is affected not only by type of initiator but also by aqueous media. This model constitutes a useful system to study formation of lipid peroxidation intermediaries and products in an aqueous environment [3]. Furthermore, using rod outer segments and/or liposomes made of retinal lipids, we have analyzed the effect of alpha-tocopherol, all-trans retinol, and retinyl palmitate on the nonenzymatic lipid peroxidation of rod outer segments [2]; the selective inhibition of the nonenzymatic lipid peroxidation of phosphatidylserine in rod outer segments by alpha-tocopherol [4]. We have studied also how retinal fatty acid binding protein reduces lipid peroxidation stimulated by long chain fatty acid hydroperoxides on rod outer segments [5], the protective effect of indoleamines on in vitro ascorbate-Fe2+-dependent lipid peroxidation of rod outer segment membranes of bovine retina [6], and lipid-protein modifications during ascorbate-Fe2+ peroxidation of photoreceptor membranes—protective effect of melatonin [7]. In addition, we have determined that melatonin and structural analogues do not possess antioxidant properties on Fe (2+)-initiated peroxidation of sonicated

It has been attractive to follow the field of photoreceptor cell damage research during almost three decades. Quantitative proteomics and lipidomics analysis are now accessible for measurement of the main components of the photoreceptor cell. From my experience, it is impossible to predict which aspects of photoreceptor cell

Studies in the author laboratory were supported by PIP 2008-0157 and PIP 4097, granted to AC National Research Council (CONICET) and Secretaría de Ciencia y Técnica, Universidad Nacional de La Plata. Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) PICT-13399 and bilateral Grant

*DOI: http://dx.doi.org/10.5772/intechopen.87240*

*Prologue: My Experience with Photoreceptors - The Peroxidation of Lipids DOI: http://dx.doi.org/10.5772/intechopen.87240*

by dynamic light-scattering were submitted to lipid peroxidation, under air atmosphere at 22°C, with Fe(2+) or Fe(3+) as initiator, in different aqueous media. We verified that peroxidation of liposomes made of retinal lipids is affected not only by type of initiator but also by aqueous media. This model constitutes a useful system to study formation of lipid peroxidation intermediaries and products in an aqueous environment [3]. Furthermore, using rod outer segments and/or liposomes made of retinal lipids, we have analyzed the effect of alpha-tocopherol, all-trans retinol, and retinyl palmitate on the nonenzymatic lipid peroxidation of rod outer segments [2]; the selective inhibition of the nonenzymatic lipid peroxidation of phosphatidylserine in rod outer segments by alpha-tocopherol [4]. We have studied also how retinal fatty acid binding protein reduces lipid peroxidation stimulated by long chain fatty acid hydroperoxides on rod outer segments [5], the protective effect of indoleamines on in vitro ascorbate-Fe2+-dependent lipid peroxidation of rod outer segment membranes of bovine retina [6], and lipid-protein modifications during ascorbate-Fe2+ peroxidation of photoreceptor membranes—protective effect of melatonin [7]. In addition, we have determined that melatonin and structural analogues do not possess antioxidant properties on Fe (2+)-initiated peroxidation of sonicated liposomes made of retinal lipids [8]; for reviews, see [9, 10].
