[Alteration of frog in vitro electroretinographic c-wave in modified extracellular cation concentration].
Effects of extracellular cation (Ca2+, Mg2+, Na+) concentrations on the electroretinographic c-wave were studied in the isolated neural retina-retinal pigment epithelium-choroid tissue of the bullfrog. Among the conditions studied (Ca2+, 0.5-5.0 mM: Mg2+, 0.5-5.0 mM: Na2+, 89.0-109.0 mM), only Ca2+ concentration significantly affected the c-wave. Between 1.0 mM and 5.0 mM Ca2+, the amplitude and the rise time (interval from the light onset to 90% amplitude) of the c-wave were positively and reversely correlated to Ca2+ concentration, respectively. The present results suggest that Ca2+ is one of the major determinants in the extracellular milieu on the c-wave, which is presumably due to its effects on the photoreceptoral activities.
Department of Ophthalmology, Kanazawa University School of Medicine, Japan.
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M
Takahira
Y
Y
Shirao
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002412:Cations; D004596:Electroretinography; D005110:Extracellular Space / Q000378:metabolism*; D066298:In Vitro Techniques; D008274:Magnesium / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000502:physiology; D011892:Rana catesbeiana; D012964:Sodium / Q000378:metabolism*
D002412:Cations; D012964:Sodium; D008274:Magnesium; D002118:Calcium