猫视网膜色素上皮的延迟性基底超极化及其与直流视网膜电图快速振荡的关系。
Delayed basal hyperpolarization of cat retinal pigment epithelium and its relation to the fast oscillation of the DC electroretinogram.
作者信息
Linsenmeier R A, Steinberg R H
出版信息
J Gen Physiol. 1984 Feb;83(2):213-32. doi: 10.1085/jgp.83.2.213.
Previous work has shown that the cat retinal pigment epithelium (RPE) is the source of two potential changes that follow the absorption of light by photoreceptors: a hyperpolarization of the apical membrane, peaking in 2-4 s, which leads to the RPE component of the electroretinogram (ERG) c-wave, and a depolarization of the basal membrane, peaking in 5 min, which leads to the light peak. This paper describes a new basal membrane response of intermediate time course, called the delayed basal hyperpolarization. Isolation of this response from other RPE potentials showed that with maintained illumination the hyperpolarization begins approximately 2 s after light onset, peaks in 20 s, and slowly ends as the membrane repolarizes over the next 60 s. The delayed basal hyperpolarization is very small for stimuli less than 4 s in duration and grows with duration, becoming approximately 15% as large as the preceding apical hyperpolarization with stimuli longer than 20 s. Extracellularly, this response contributes to the transepithelial potential (TEP) across the RPE. In response to light the TEP first rises to a peak, the c-wave, as the apical membrane hyperpolarizes. For stimuli longer than approximately 4 s, the decline of the TEP from the peak of the c-wave results partly from the recovery of apical membrane potential and partly from the delayed basal hyperpolarization. For long periods of illumination (300 s) the delayed basal hyperpolarization leads to a trough in the TEP between the c-wave and light peak. This trough is largely responsible for a corresponding trough in vitreal recordings, which has been called the "fast oscillation." The term "fast oscillation" has also been used to denote the sequence of potential changes resulting from repeated stimuli approximately 1 min in duration. In addition to the delayed basal hyperpolarization, such responses also contain a basal off-response, a delayed depolarization.
先前的研究表明，猫视网膜色素上皮（RPE）是光感受器吸收光后发生的两种潜在变化的来源：顶膜超极化，在2 - 4秒达到峰值，这导致视网膜电图（ERG）c波的RPE成分；以及基底膜去极化，在5分钟达到峰值，这导致光峰。本文描述了一种具有中间时程的新的基底膜反应，称为延迟基底超极化。将这种反应与其他RPE电位分离后发现，在持续光照下，超极化在光照开始后约2秒开始，在20秒达到峰值，并在接下来的60秒内随着膜复极化而缓慢结束。对于持续时间小于4秒的刺激，延迟基底超极化非常小，并随持续时间增加，对于持续时间超过20秒的刺激，其大小约为先前顶膜超极化的15%。在细胞外，这种反应有助于跨RPE的跨上皮电位（TEP）。对光的反应中，随着顶膜超极化，TEP首先上升到峰值，即c波。对于持续时间超过约4秒的刺激，TEP从c波峰值下降部分是由于顶膜电位的恢复，部分是由于延迟基底超极化。对于长时间光照（300秒），延迟基底超极化导致TEP在c波和光峰之间出现一个低谷。这个低谷在很大程度上导致了玻璃体记录中的相应低谷，这被称为“快速振荡”。术语“快速振荡”也被用于表示由持续时间约1分钟的重复刺激引起的电位变化序列。除了延迟基底超极化外，这种反应还包含一个基底关闭反应，即延迟去极化。
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