|Yokoi, Katsuhiko - SEITOKU UNIV|
|Newman Jr, Samuel|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2003
Publication Date: March 24, 2004
Citation: Yokoi, K., Uthus, E.O., Penland, J.G., Newman Jr, S.M., Nielsen, F.H. 2004. Nickel deficiency alters eye mitochondrial morphology and impairs brightness discrimination of rats [abstract]. The Federation of American Societies for Experimental Biology Journal. 18(4):A527. Technical Abstract: Because nickel (Ni) activates cyclic nucleotide-gated cation channels of retinal rods (Gordon, Neuron 14:857, 1995), we tested the hypothesis that Ni deficiency alters eye morphology and visual acuity (brightness discrimination) of rats. Weanling male Sprague-Dawley rats were assigned to groups of 8 in a factorially arranged experiment with dietary variables of supplemental sodium chloride (NaCl; 0 or 80 g/kg) and Ni (0 or 1 mg/kg). Basal diet contained 15 - 40 ng Ni/g. After being fed their respective diet for 14 weeks, brightness discrimination of each rat was assessed by measuring the time spent under a black vs transparent plexiglas cover of a Y-maze. Each animal was placed in the third arm which was covered by transparent plexiglas. Six 60-second sessions, each with a different placement of the dark and light arms, were video recorded for later analysis. With 10 lux of light, Ni deprivation and excessive NaCl independently decreased (p< 0.01) the time spent in the dark arm. Two weeks after testing, retinas were examined by transmission electron microscopy. Cristae abundance in 7 measured mitochondria from rod inner segments of each rat was significantly decreased (25%) by Ni deprivation in the absence of supplemental NaCl. The results support the hypothesis that Ni has a physiological role that affects visual signal transmission including light detection by retinal rods. Support: NiPERA and Salt Science Foundation.