The eel retina. Receptor classes and spectral mechanisms.

Open Access
Publisher Website
Google Scholar
Abstract
Light microscopy and EM revealed that there are rods and cones in the retina of the eel Anguilla rostrata. The rods predominated with a rod to cone ratio of 150:1. The spectral sensitivity of the dark-adapted eyecup ERG [electroretinogram] had a peak at about 520 nm and was fit well by a vitamin A2 nomogram pigment with a .lambda.max = 520 nm. This agreed with the eel photopigment measurements of other investigators. This result implied that a single spectral mechanism, the rods, provided the input for the dark-adapted ERG. The spectral sensitivity of the ERG to flicker in the light-adapted eyecup preparation was shifted to longer wavelengths; it peaked at around 550 nm. There was evidence that this technique might not have completely eliminated rod intrusion. Rod responses were abolished in a bleached isolated retina preparation, in which it was shown that there were 2 classes of cone-like mechanisms, one with .lambda.max of 550 nm and the other with .lambda.max of < 450 nm. Ganglion cell recording provided preliminary evidence for opponent-color processing. Horizontal cells were only of the L type with rod and cone inputs.