Dick E, Miller R F, Bloomfield S
J Gen Physiol. 1985 Jun;85(6):911-31. doi: 10.1085/jgp.85.6.911.
Electroretinogram (ERG) and extracellular potassium activity (K+o) measurements were carried out in isolated superfused rabbit eyecup preparations under control conditions and during the application of pharmacological agents that selectively modify the light-responsive retinal network. Light-evoked K+o changes in the rabbit (E-type) retina resemble those previously described in amphibian (I-type) retinas. Different components of the light-evoked K+o changes can be distinguished on the bases of retinal depth, V vs. log I properties, and their responses to pharmacological agents. We find two separable sources of light-evoked increases in extracellular K+: a proximal source and a distal source. The properties of the distal light-evoked K+o increase are consistent with the hypothesis that it initiates a K+-mediated current through Müller cells that is detected as the primary voltage of the electroretinographic b-wave. These experiments also support previous studies indicating that both the corneal-positive component of c-wave and the corneal-negative slow PIII potential result from K+-mediated influences on, respectively, the retinal pigment epithelium and Müller cells.
在对照条件下以及应用选择性改变光反应性视网膜网络的药物制剂期间，对分离的灌注兔眼杯标本进行视网膜电图（ERG）和细胞外钾活性（K+o）测量。兔（E型）视网膜中光诱发的K+o变化类似于先前在两栖动物（I型）视网膜中描述的变化。基于视网膜深度、V与log I特性及其对药物制剂的反应，可以区分光诱发的K+o变化的不同成分。我们发现细胞外K+光诱发增加有两个可分离的来源：近端来源和远端来源。远端光诱发的K+o增加的特性与以下假设一致，即它通过Müller细胞引发K+介导的电流，该电流被检测为视网膜电图b波的初级电压。这些实验也支持先前的研究，表明角膜正性成分和角膜负性慢PIII电位分别是由K+对视网膜色素上皮和Müller细胞的介导影响所致。
