Physiological features of the S- and M-cone photoreceptors of wild-type mice from single-cell recordings.
Physiological features of the S- and M-cone photoreceptors of wild-type mice from single-cell recordings.
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DOI：
10.1085/jgp.200609490
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发表时间：
2006-04
期刊：
影响因子：
--
通讯作者：
Pugh EN Jr
中科院分区：
文献类型：
--
作者：
Nikonov SS;Kholodenko R;Lem J;Pugh EN Jr
视锥细胞仅占野生型（WT）小鼠光感受器的3%。虽然已经用吸管记录其外段膜电流对小鼠视杆细胞进行了彻底研究，但迄今为止尚未发表WT视锥细胞的记录，这可能是因为视锥细胞的稀有性及其外段的脆弱性。最近，我们对Nrl −/−小鼠的光感受器进行了表征，使用吸管记录了它们的“内节”（核周区域），并发现它们是锥体。在这里，我们报告使用相同的方法首次记录了WT小鼠和缺乏G蛋白转导素α亚基（G tα-/-）的小鼠的单视锥细胞的反应，这种损失使它们在功能上无杆。发现大多数视锥在功能上共表达S-（λmax = 360 nm）和M-（λmax = 508 nm）视锥视蛋白，并且在360 nm处最敏感（“S-视锥”）;然而，发现来自背侧视网膜的所有视锥在508 nm处最敏感（“M-视锥”）。S-和M-视锥的微光响应动力学和绝对灵敏度非常相似，并且不依赖于共表达的视锥视蛋白驱动转导;微光响应的峰值时间为10.70 ms，并且每次光异构化抑制了10.2%的循环电流。野生型视锥细胞中的扩增（A 4 s−2）比视杆细胞中的扩增（A 8 s−2）低两倍。小鼠M-视锥细胞将其循环电流维持在非常接近暗适应水平，即使当>90%的M-视蛋白被漂白时。S-视锥细胞对漂白的S-视蛋白的耐受性低于M-视锥细胞对漂白的M-视蛋白的耐受性，但仍然比小鼠视杆细胞对漂白的视紫红质的耐受性高得多，后者在20%漂白后表现出其循环电流的近50%的持续抑制。因此，这三种类型的小鼠视蛋白在它们的漂白的、未再生的视蛋白产生“暗光”的程度上看起来是不同的。
Cone cells constitute only 3% of the photoreceptors of the wild-type (WT) mouse. While mouse rods have been thoroughly investigated with suction pipette recordings of their outer segment membrane currents, to date no recordings from WT cones have been published, likely because of the rarity of cones and the fragility of their outer segments. Recently, we characterized the photoreceptors of Nrl −/− mice, using suction pipette recordings from their “inner segments” (perinuclear region), and found them to be cones. Here we report the use of this same method to record for the first time the responses of single cones of WT mice, and of mice lacking the α-subunit of the G-protein transducin (G tα−/−), a loss that renders them functionally rodless. Most cones were found to functionally co-express both S- (λmax = 360 nm) and M- (λmax = 508 nm) cone opsins and to be maximally sensitive at 360 nm (“S-cones”); nonetheless, all cones from the dorsal retina were found to be maximally sensitive at 508 nm (“M-cones”). The dim-flash response kinetics and absolute sensitivity of S- and M-cones were very similar and not dependent on which of the coexpressed cone opsins drove transduction; the time to peak of the dim-flash response was ∼70 ms, and ∼0.2% of the circulating current was suppressed per photoisomerization. Amplification in WT cones (A ∼4 s−2) was found to be about twofold lower than in rods (A ∼8 s−2). Mouse M-cones maintained their circulating current at very nearly the dark adapted level even when >90% of their M-opsin was bleached. S-cones were less tolerant to bleached S-opsin than M-cones to bleached M-opsin, but still far more tolerant than mouse rods to bleached rhodopsin, which exhibit persistent suppression of nearly 50% of their circulating current following a 20% bleach. Thus, the three types of mouse opsin appear distinctive in the degree to which their bleached, unregenerated opsins generate “dark light.”
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DOI：
10.1085/jgp.106.3.543
发表时间：
1995-09
期刊：
The Journal of general physiology
影响因子：
--
作者：
Cornwall MC;Matthews HR;Crouch RK;Fain GL
通讯作者：
Fain GL
具有光感受器中存在的以太触发通道的表征显示出与杆内段中的K+电流IKX相似性。
影响因子：
3.8
作者：
Frings, S;Brüll, N;Dzeja, C;Angele, A;Hagen, V;Kaupp, UB;Baumann, A
通讯作者：
Baumann, A
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：
2.5
作者：
Ghosh, KK;Bujan, S;Wässle, H
通讯作者：
Wässle, H
影响因子：
1.8
作者：
LAMB, TD
通讯作者：
LAMB, TD