视网膜电图显示暗适应青蛙视网膜中视锥信号的抑制。

Suppression of cone signal in the dark-adapted frog retina as indicated by the electroretinogram.

作者信息

Fatechand R

出版信息

Rev Can Biol. 1978 Jun;37(2):101-13.

Abstract

Electroretinogram (ERG) cone acitvity is depressed in the dark-adapted frog retina. The strength of this effect is examined over a large range of flash energy, for 618 nm flashes extending up to about 4 log10 units above the "threshold" (10-25 micron V b-wave) of the cone ERG "released" in the early stage of rapid dark-adaptation (RDA). Cone signal depression is remarkably strong over this flash energy range. The cone ERG is practically absent for flashes up to about I log unit above cone RDA threshold. For stronger flashes, the suppression becomes time-dependent, that is, cone signal is very small for the first few hundred msec. after the flash, cone intrusion then becoming detectable. The results suggest that the cone suppression phenomena arises distally in the retina, probably near the receptor layer, and that cone signal intrusion a few hundred msec. after a strong flash may be due to light-adaptation of rods by the flash itself.

摘要

在暗适应的青蛙视网膜中，视网膜电图（ERG）的视锥细胞活性受到抑制。在大范围的闪光能量下研究了这种效应的强度，对于618纳米的闪光，其能量比快速暗适应（RDA）早期“释放”的视锥细胞ERG的“阈值”（10 - 25微伏b波）高出约4个对数单位。在这个闪光能量范围内，视锥细胞信号抑制非常强烈。对于高于视锥细胞RDA阈值约1个对数单位的闪光，视锥细胞ERG实际上消失了。对于更强的闪光，抑制变得与时间相关，也就是说，在闪光后的最初几百毫秒内视锥细胞信号非常小，之后视锥细胞信号开始变得可检测到。结果表明，视锥细胞抑制现象出现在视网膜的远端，可能靠近感受器层，并且在强闪光后几百毫秒视锥细胞信号的出现可能是由于闪光本身使视杆细胞发生了光适应。