Photoreceptor disc shedding in eye cups. Inhibition by deletion of extracellular divalent cations. Invest Ophthalmol Vis Sci 1983 Nov;24(11):1456-64
Date
11/01/1983Pubmed ID
6642925Scopus ID
2-s2.0-0021038279 (requires institutional sign-in at Scopus site) 27 CitationsAbstract
To further define the medium requirements for in vitro rod disc shedding and phagocytosis in eye cups of Xenopus laevis, the effect of deletion of divalent cations was examined. Calcium-free medium completely eliminated both normal diurnal disc shedding (initiated by light onset) and dark-primed disc shedding (initiated by a period of darkness followed by additional darkness or light). The effect was reversible. Furthermore, the events that occurred during the initial dark-priming period did not require extracellular millimolar calcium, since the addition of calcium (1.8 mM) after an initial hour of darkness in calcium-free medium resulted in a marked increase in disc shedding, regardless of the subsequent lighting condition. Magnesium-free medium did not inhibit light-evoked shedding. However, magnesium-free medium partially inhibited disc shedding in one of the two lighting paradigms used to elicit dark-primed disc shedding. This suggests that the extracellular divalent cation requirement varies for different lighting paradigms that promote shedding. The inhibition of disc shedding by magnesium-free medium was morphologically distinct from calcium-free medium; the inhibition in magnesium-free medium was correlated uniquely with a reduction in the interdigitation between the photoreceptor and the retinal pigment epithelium.
Author List
Greenberger LM, Besharse JCAuthor
Joseph C. Besharse PhD, MA Emeritus Professor in the Cell Biology Neurobiology and Anatomy department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCalcium
Culture Media
In Vitro Techniques
Magnesium
Phagocytosis
Photoreceptor Cells
Xenopus laevis
