Retinal functions

There were no treatment-related effects on retinal function and no morphological effects on the eyes of dogs that were exposed to 0.03, 0.30, or 3.00 mg/kg/day methyl parathion for 13 weeks and allowed 4 weeks of no exposure to recover (Daly 1989). 

Cuppers, C. and E. Wagner (1950). Pharmacological effect on retinal function normal dark adaptation (German). Klin Monatsbldtter Augenheilkd 117(1) 59-69. 

Astaxanthin has been suggested as a potential dietary supplement to improve retinal function (Hussein et al., 2006 Parisi et al., 2008). While normally astaxanthin is not present in human plasma, a high dose of dietary astaxanthin does result in its appearance in appreciable concentrations within the plasma where it is bound mainly to the lipoproteins, VLDL, LDL, and HDL (Coral-Hinostroza et al., 2004). To our knowledge, to date there is no report identifying astaxanthin in human retina. 

Condeelis J (1993) Life at the leading edge the formation of cell protrusions. Annu Rev Cell Biol 9 411 44 Da T, Verkman AS (2004) Aquaporin-4 gene disruption in mice protects against impaired retinal function and cell death after ischemia. Invest Ophthalmol Vis Sci 45 4477 483 Deen PM, Verdijk MA, Knoers NV, Wieringa B, Monnens LA, van Os CH, van Oost BA (1994) Requirement of human renal water channel aquaporin-2 for vasopressin-dependent concentration of urine. Science 264 92-95... 

Li 1, Patil RV, Verkman AS (2002) Mildly abnormal retinal function in transgenic mice without Muller cell aquaporin-4 water channels. Invest Ophthalmol Vis Sci 43 573—579 Ma T, Yang B, Gillespie A, Carlson El, Epstein Cl, Verkman AS (1997) Generation and phenotype of a transgenic knockout mouse lacking the mercurial-insensitive water channel aquaporin-4. 1 Clin Invest 100 957-962... 

Parkinson, T.M., et al. 2000. The effects of in vivo iontophoresis on rabbit eye structure and retinal function. Invest Ophthalmol Vis Sci 41 S772. 

The effect of FTIs on retinal function also needs to be carefully examined. Several proteins involved in retinal signal transduction are farnesylated in vivo, presumably by FTase. These include rod cell cGMP phosphodiesterase a-subunit,108,109 rod cell transducin y-subunit,110,111 and rhodopsin kinase.112 Since the retina consists of terminally differentiated, nondividing cells, the anti-proliferative properties of FTIs should be inconsequential. Visual function could possibly be affected by alterations in the prenylation of proteins involved in retinal signal transduction, although any changes of this sort should be reversible. 

The structure of 4-substituted 3,5-bis(2-pyridyl)pyrazoles [245], seventeen C-nitropyrazoles affected ocular blood flow and retinal function recovery after ischemic insult [244], and a large series of nitroazoloanhydrosacchares [295] has been determined by II and 13C NMR method. 

Generator of NO [272], ocular pharmacology and therapeutics (ocular blood flow, recovery of retinal function after ischemic insult) [273]... 

It is also fairly easy to perform specialized measurements such as electroretinography in dogs without the anesthesia or surgical preparation required in other species. ° Electroretinography has assumed a status of increased importance in safety evaluation because many drugs affect retinal function. Examples are the quinolone antibacterials and Viagra. ... 

In contrast, in another study there was partial reversibility of visual field constriction and retinal function after withdrawal in two patients (57). 

Coupland SG, Zackon DH, Leonard BC, Ross TM. Vigabatrin effect on inner retinal function. Ophthalmology 2001 108(8) 1493-6. 

Warner, R., Laughame, J., Peet, M., Brown, L. and Rogers, N. (1999) Retinal function as a marker for cell membrane omega-3 fatty acid depletion in schizophrenia a pilot study. Biol. Psychiatry. 45 1138-1142. 

Goldstein IM, Ostwald P, Roth S. 1996. Nitric oxide A review of its role in retinal function and disease. Vis Res 36 2979-2994. 

Uauy RD, Birch DG, Birch EE, Tyson JE, Hoffman DR, Effect of dietary omega-3-fatty-acids on retinal function of very-low-bhth-weight neonates, Pediatr Res 1990 28(5) 485 92. 

The Role of Omega-3 Polyunsaturated Fatty Acids in Retinal Function... 

It is apparent that the central nervous system, and retina in particular, appears to go to greatlengths to sustain its levels of DHA. The following discussion will consider biological membranes and retinal function and discuss the possible role that DHA has in its physiology. 

The earliest studies investigating the effects of n-3 dietary fatty acid manipulation on vision date back to the early 1970s. Benolken and others (1973) fed rats a fat-free diet, which resulted in a 60% reduction in the retinal DHA content. This was associated with reductions in the amplitudes of the ERG a-wave (and b-wave), reflecting anomalous photoreceptor function. In a later study, the same authors (Wheeler et al., 1975) studied the effects of feeding rats diets free of fat or supplemented with either n-9, n-6, or n-3 precursors. They determined that rats showed increased ERG amplitudes when fed 2% (w/w) linoleic acid (18 2n-6, LA), but an even greater response when 2% (w/w) a-linolenic acid (18 3n-3, ALA) was used. A mixture of 1% (w/w) LA and 1% (w/w) ALA gave an intermediate response, implying that n-3 fatty acids were critical for the development of optimal retinal function. 

The literature poses many interesting questions regarding the necessity of long-chain n-3 fatty acids in neural function and development. The next subsection will further elucidate the role of these molecules in retinal function. Several models have been proposed on a biomolecular and biophysical level, which go some way to explaining some of the functional changes. 

Leat WMF, Curtis R, Millichamp NJ, et al. Retinal function in rats and guinea pigs reared on diets low in essential fatty acids and supplemented with linoleic or linolenic acids. Ann Nutr Metab 1986 30 166-174. 

Brightness-Discrimination Learning Behavior and Retinal Function Affected by Long-Term a-Linolenic Acid Deficiency in Rat... 

Chapter 13 / Brightness-Discrimination Learning and Retinal Function... 

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