Dawis S M, Rossetto M
Laboratory of Biophysics, Rockefeller University, New York, NY 10021.
Vis Neurosci. 1993 Jul-Aug;10(4):687-92. doi: 10.1017/s0952523800005381.
We have developed an optical method to monitor the activity of the ON and OFF channels in the anuran retina. The change in the fraction of near infrared that is transmitted transversely through the retina in an eyecup slice is monitored during stimulation by visible, green light. Near-infrared transmission increases both at the onset and at the termination of a step stimulus. This "ON/OFF" response is maximal in the neural retina. Sodium L-aspartate, which blocks the light-evoked activity of post-photoreceptor neurons, abolishes the "ON/OFF" response. L-AP4, used as a selective blocker of the ON channel, reduces the "ON" component and has little or no effect on the "OFF" component. The "ON" and "OFF" processes observed optically are distinct from those that generate the b- and d-waves of the electroretinogram, and the "ON" and "OFF" components may be superior to the b- and d-waves as indicators of ON and OFF channel activity. The optical method is almost as simple as electroretinography and has the advantages that responses can be spatially localized with ease.
我们开发了一种光学方法来监测无尾目动物视网膜中开通道和关通道的活性。在眼杯切片中，当用可见的绿光进行刺激时，监测横向透过视网膜的近红外光比例的变化。在阶跃刺激开始和结束时，近红外光透射率均增加。这种“开/关”反应在神经视网膜中最为明显。L-天冬氨酸钠可阻断光感受器后神经元的光诱发活性，消除“开/关”反应。L-AP4用作开通道的选择性阻断剂，可降低“开”成分，对“关”成分几乎没有影响。通过光学观察到的“开”和“关”过程与产生视网膜电图的b波和d波的过程不同，并且“开”和“关”成分作为开通道和关通道活性的指标可能优于b波和d波。该光学方法几乎与视网膜电图一样简单，并且具有可以轻松地在空间上定位反应的优点。
