Localization of calcium and barium in toad retina by secondary ion mass spectrometry
Brain ResearchPublished 1 September 1981
M. S. Burns, David M. File, Kenneth T. Brown, Dale G. Flaming
Citations18
SJR quartileQ2
SJR score0.85
SNIP0.72
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TL;DR
Calcium and barium are found in melanin granules of toad retinal pigment epithelial cells and choroidal melanocytes and this suggests that barium may not serve a major role in the normal processes of dark adaptation in vertebrate photoreceptors.
Abstract
Calcium and barium are found in melanin granules of toad retinal pigment epithelial cells and choroidal melanocytes. Calcium, but not barium, was found in photoreceptor outer segments and this suggests that barium may not serve a major role in the normal processes of dark adaptation in vertebrate photoreceptors.
Keywords
Biochemistry, Genetics and Molecular Biology
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In particular, studies using isotope discrimination, quantitative analysis and depth profiling will enhance the usefulness of SIMS as a technique for biological research.
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Secondary ion mass spectrometry (SIMS) showed that barium was located in the rod outer and inner segment of cat, and was relatively less intense in nuclei, suggesting thatbarium may be an important participant in the ionic events governing photoreceptor physiology.
Proceedings of the National Academy of SciencesOpposing effects of calcium and barium in vertebrate rod photoreceptors
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Intracellular recording in outer segments of red rods of the toad retina showed that increasing Ca(2+) concentration in the perfusate mimicked certain aspects of light adaptation, providing further support for the hypothesis that Ca (2+) acts as an internal transmitter that is subject to light-induced release from the rod saccules.
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All three phases of the pigment cell response in the frog eye have spectral response curves which are essentially flat through the major portion of the visible range, thus all three phases appear to be mediated by a single photopigment which is a form of melanin.
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