Ionic channels of the inner segment of tiger salamander cone photoreceptors.
Ionic channels of the inner segment of tiger salamander cone photoreceptors.
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老虎sallamander锥形感受器的内部段的离子通道。
DOI：
10.1085/jgp.94.4.719
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发表时间：
1989-10
影响因子：
3.8
通讯作者：
HILLE, B
中科院分区：
文献类型：
--
作者：
BARNES, S;HILLE, B
通过酶法分离视锥细胞，并通过全细胞、千兆密封电压钳技术研究它们的离子电流。确定了五种非突触电流。显着的、选择性差的阳离子电流 Ih 在超极化过程中延迟一段时间后激活，然后在返回到大于 -50 mV 的电位时延迟一段时间后停用。开发了具有三个打开状态和两个关闭状态的 Ih 门控动力学经验模型。去极化会引发一个小的电压门控钙电流 (ICa)。尼群地平、镍、镉和钴的阻断、钡电流的增加、缺乏快速失活以及相对较高的阈值表明存在 L 型 Ca 通道。没有发现低阈值 Ca 通道的证据。脉冲后存在阴离子电流 ICl(Ca)，导致显着的向内 ICa（但不是 IBa），并且当存在钴时不会引起阴离子电流 ICl(Ca)。短时间去极化后 ICl(Ca) 的尾部较短（100 ms），较长时间去极化后较长。去极化还引发了两个 TEA 敏感 K 电流。一种是 IK(Ca)，对钙敏感。我们寻找多种神经递质对 Ih、ICa 和 ICl(Ca) 的调节。当使用 GABA 或腺苷时，Ih 没有变化，但少数视锥细胞中的 ICa 和 ICl(Ca) 降低。我们讨论了当周围视锥细胞被照亮时，这种调制如何影响视锥细胞上水平细胞的反馈效应。
Cone photoreceptors were isolated enzymatically and their ionic currents studied by the whole-cell, gigaseal voltage-clamp technique. Five nonsynaptic currents were identified. A prominent, poorly selective cation current, Ih, activated after a delay during hyperpolarizations and then deactivated with a delay on return to potentials greater than -50 mV. An empirical model for Ih gating kinetics is developed with three open and two closed states. Depolarization elicits a small, voltage-gated calcium current (ICa). Block by nitrendipine, nickel, cadmium, and cobalt, increase of current with barium, lack of rapid inactivation, and relatively high threshold suggest an L-type Ca channel. No evidence was found for low-threshold Ca channels. An anion current ICl(Ca) was present after pulses that led to a significant inward ICa (but not IBa) and was not elicited when cobalt was present. Tails of ICl(Ca) were short (100 ms) after short depolarizations and were longer after longer depolarizations. Two TEA- sensitive K currents were also elicited by depolarizations. One, IK(Ca), was calcium sensitive. We looked for modulation of Ih, ICa, and ICl(Ca) by a number of neurotransmitters. No changes of Ih were seen, but ICa and ICl(Ca) were depressed in a few cones when GABA or adenosine were applied. We discuss how this modulation might contribute to the feedback effects of horizontal cells on cones when surrounding cones are illuminated.
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影响因子：
5.5
作者：
ATTWELL, D;WERBLIN, FS;WILSON, M
通讯作者：
WILSON, M
影响因子：
5.5
作者：
BADER, CR;BERTRAND, D
通讯作者：
BERTRAND, D
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：
COREY, DP;DUBINSKY, JM;SCHWARTZ, EA
通讯作者：
SCHWARTZ, EA
影响因子：
5.5
作者：
DIFRANCESCO, D
通讯作者：
DIFRANCESCO, D