Bicarbonate boosts flash response amplitude to augment absolute sensitivity and extend dynamic range in murine retinal rods.
Bicarbonate boosts flash response amplitude to augment absolute sensitivity and extend dynamic range in murine retinal rods.
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DOI：
10.3389/fnmol.2023.1125006
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发表时间：
2023
影响因子：
4.8
通讯作者：
Makino, Clint L.
中科院分区：
文献类型：
--
作者：
Adhikari, Rajan D.;Kossoff, Amanda M.;Cornwall, M. Carter;Makino, Clint L.
视网膜中的视杆光感受器调节它们的反应性和灵敏度，使得它们可以在宽范围的光强度下继续提供有意义的信息。通过刺激外节中的膜鸟苷酸环化酶以更快的速率以Ca2+依赖的方式合成cGMP，碳酸氢盐增加了循环的“暗”电流，并加速了两栖动物杆中的闪光反应动力学。与两栖动物的视杆细胞相比，哺乳动物的视杆细胞体积更小，在更高的温度下工作，表达的视觉级联反应蛋白具有不同的生化特性。在这里，我们评估了重碳酸盐在cpfl3小鼠视杆细胞中的作用。这些小鼠缺乏功能性视锥细胞转导蛋白Gnat 2的表达，使得视锥细胞对光非常不敏感，因此在视网膜电图记录中可以单独观察到视杆细胞对光的反应。Biccadine增加暗电流和绝对灵敏度和加快闪光反应的恢复在更大程度上比两栖类杆。此外，碳酸氢盐使小鼠视杆细胞能够在一个范围内作出反应，该范围延伸到较暗的闪光。较大的闪光反应可能导致部分从碳酸氢盐诱导的升高细胞内pH值。然而，高pH值单独闪光反应恢复动力学的影响不大，甚至抑制了碳酸氢盐的加速作用，与直接的，调节作用的碳酸氢盐对Ca2+依赖，膜鸟苷酸环化酶活性。
Rod photoreceptors in the retina adjust their responsiveness and sensitivity so that they can continue to provide meaningful information over a wide range of light intensities. By stimulating membrane guanylate cyclases in the outer segment to synthesize cGMP at a faster rate in a Ca2+-dependent fashion, bicarbonate increases the circulating “dark” current and accelerates flash response kinetics in amphibian rods. Compared to amphibian rods, mammalian rods are smaller in size, operate at a higher temperature, and express visual cascade proteins with somewhat different biochemical properties. Here, we evaluated the role of bicarbonate in rods of cpfl3 mice. These mice are deficient in their expression of functional cone transducin, Gnat2, making cones very insensitive to light, so the rod response to light could be observed in isolation in electroretinogram recordings. Bicarbonate increased the dark current and absolute sensitivity and quickened flash response recovery in mouse rods to a greater extent than in amphibian rods. In addition, bicarbonate enabled mouse rods to respond over a range that extended to dimmer flashes. Larger flash responses may have resulted in part from a bicarbonate-induced elevation in intracellular pH. However, high pH alone had little effect on flash response recovery kinetics and even suppressed the accelerating effect of bicarbonate, consistent with a direct, modulatory action of bicarbonate on Ca2+- dependent, membrane guanylate cyclase activity.
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影响因子：
2.5
作者：
COLEMAN, PA;CARRAS, PL;MILLER, RF
通讯作者：
MILLER, RF
DOI：
10.1073/pnas.250478897
发表时间：
2000-12-05
影响因子：
11.1
作者：
Calvert, PD;Krasnoperova, NV;Lem, J
通讯作者：
Lem, J
影响因子：
5.5
作者：
BADER, CR;BERTRAND, D;SCHWARTZ, EA
通讯作者：
SCHWARTZ, EA
影响因子：
5.5
作者：
DONNER, K;HEMILA, S;SHEVCHENKO, T
通讯作者：
SHEVCHENKO, T
影响因子：
3.4
作者：
Ochrietor, JD;Clamp, MF;Linser, PJ
通讯作者：
Linser, PJ