دورية أكاديمية
Light dependence of calcium and membrane potential measured in blowfly photoreceptors in vivo
| العنوان: | Light dependence of calcium and membrane potential measured in blowfly photoreceptors in vivo |
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| المؤلفون: | Oberwinkler, Johannes, Stavenga, Doekele G. |
| المصدر: | Oberwinkler , J & Stavenga , D G 1998 , ' Light dependence of calcium and membrane potential measured in blowfly photoreceptors in vivo ' , Journal of general physiology , vol. 112 , no. 2 , pp. 113-124 . https://doi.org/10.1085/jgp.112.2.113Test |
| سنة النشر: | 1998 |
| المجموعة: | University of Groningen research database |
| مصطلحات موضوعية: | phototransduction, light adaptation, calcium buffering, calcium homeostasis, fluorescent calcium indicators, LIMULUS VENTRAL PHOTORECEPTORS, INDUCED CA2+ INFLUX, HONEY-BEE DRONE, DROSOPHILA PHOTORECEPTORS, FLY PHOTORECEPTORS, EXTRACELLULAR CALCIUM, SENSITIVE CHANNELS, APIS-MELLIFERA, COMPOUND EYE, OXIDATIVE-METABOLISM |
| الوصف: | Light adaptation in insect photoreceptors is caused by an increase in the cytosolic Ca2+ concentration. To better understand this process, we measured the cytosolic Ca2+ concentration in vivo as a function of adapting light intensity in the white-eyed blowfly mutant chalky. We developed a technique to measure the cytosolic Ca2+ concentration under conditions as natural as possible. The calcium indicator dyes Oregon Green 1, 2, or 5N (Molecular Probes, Inc., Eugene, OR) were iontophoretically injected via an intracellular electrode into a photoreceptor cell in the intact eye; the same electrode was also used to measure the membrane potential. The blue-induced green fluorescence of these dyes could be monitored by making use of the optics of the facet lens and the rhabdomere waveguide. The use of the different Ca2+-sensitive dyes that possess different affinities for Ca2+ allowed the quantitative determination of the cytosolic Ca2+ concentration in the steady state. Determining the cytosolic Ca2+ concentration as a function of the adapting light intensity shows that the Ca2+ concentration is regulated in a graded fashion over the whole dynamic range where a photoreceptor cell can respond to light. When a photoreceptor is adapted to bright light, the cytosolic Ca2+ concentration reaches stable values higher than 10 mu M. The data are consistent with the hypothesis that the logarithm of the increase in cytosolic Ca2+ concentration is linear with the logarithm of the light intensity. From the estimated values of the cytosolic Ca2+ concentration, we conclude that the Ca2+-buffering capacity is limited. The percentage of the Ca2+ influx that is buffered gradually decreases with increasing Ca2+ concentrations; at cytosolic Ca2+ concentration levels above 10 mu M, buffering becomes minimal. |
| نوع الوثيقة: | article in journal/newspaper |
| وصف الملف: | application/pdf |
| اللغة: | English |
| العلاقة: | https://research.rug.nl/en/publications/4f9c50b4-80a5-47f0-9b19-2d64f17806ccTest |
| DOI: | 10.1085/jgp.112.2.113 |
| الإتاحة: | https://doi.org/10.1085/jgp.112.2.113Test https://hdl.handle.net/11370/4f9c50b4-80a5-47f0-9b19-2d64f17806ccTest https://research.rug.nl/en/publications/4f9c50b4-80a5-47f0-9b19-2d64f17806ccTest https://pure.rug.nl/ws/files/6655747/1998JGenPhysiolOberwinkler.pdfTest |
| حقوق: | info:eu-repo/semantics/openAccess |
| رقم الانضمام: | edsbas.C7989C9 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1085/jgp.112.2.113 |
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