title: Postnatal Deficiencies of Zinc and Taurine Alter Electroretinograms, Oscillatory Potentials and Morphology of the Rat Retina.
abstract: The study objective was to evaluate the retinal response to deficiencies of zinc and taurine present throughout the period of postnatal retinal development. At parturition, Sprague-Dawley dams were assigned to one of four treatments in a 2 × 2 factorial design with two levels of zinc (4.5 and 50 μg/g) and two levels of taurine (0 and 2 μmol/g). Guanidinoethyl sulfonate, a taurine transport inhibitor, was added to the drinking water of the rats receiving 0 μmol/g taurine. Male pups (n = 10) were weaned on to their respective diets at postnatal day 22. Dark adapted electroretinograms and oscillatory potentials (OP) were recorded in the pups at 48-57 days of age. At maximal light intensity, the amplitudes of the a- and b-waves were depressed by deficiency of either nutrient, but the influence of combining these treatments was less than additive; the same pattern was evident for Vmax, the maximum amplitude obtained when the b-wave was plotted as a function of light intensity. This type of interaction was also evident for the amplitudes of OP1, OP3 and OP4. Zinc deficiency independently decreased the amplitude and increased the latency of OP5, and increased the latencies of OP3 and OP4. Light and transmitting electron microscopic examination revealed the most pronounced retinal degeneration in the rats deficient in both zinc and taurine. Tibia zinc and liver taurine concentrations provide evidence that these nutrients also interact in other tissues. The findings of this study demonstrate retinal damage with deficiencies of zinc and taurine during postnatal life. These nutrients interact in at least some of their functions in the retina through an as yet unidentified mechanism.
authors.affiliation: a College of Pharmacy and Nutrition , Saskatoon , SK , Canada S7N 5C9.
authors.forename: P G
authors.initials: PG
authors.lastname: Paterson
authors.affiliation: b Western College of Veterinary Medicine, University of Saskatchewan , 110 Science Place, Saskatoon , SK , Canada S7N 5C9.
authors.forename: B H
authors.initials: BH
authors.lastname: Grahn
authors.affiliation: a College of Pharmacy and Nutrition , Saskatoon , SK , Canada S7N 5C9.
authors.forename: K T
authors.initials: KT
authors.lastname: Gottschall-Pass
authors.affiliation: a College of Pharmacy and Nutrition , Saskatoon , SK , Canada S7N 5C9.
authors.forename: D K
authors.initials: DK
authors.lastname: Gorecki
authors.affiliation: a College of Pharmacy and Nutrition , Saskatoon , SK , Canada S7N 5C9.
authors.forename: H A
authors.initials: HA
authors.lastname: Semple
keywords: Electroretinogram; Oscillatory potentials; Rat; Retina; Taurine deficiency; Zinc deficiency