title: The eel retina. Receptor classes and spectral mechanisms.
abstract: Light and electron microscopy revealed that there are both rods and cones in the retina of the eel Anguilla rostrata. The rods predominate with a rod to cone ratio of 150:1. The spectral sensitivity of the dark-adapted eyecup ERG had a peak at about 520 nm and was well fit by a vitamin A2 nomogram pigment with a lambdamax = 520 nm. This agrees with the eel photopigment measurements of other investigators. This result implies that a single spectral mechanism--the rods--provides 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. However, 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 two classes of cone-like mechanisms, one with lambdamax of 550 nm and the other with lambdamax of less than 450 nm. Ganglion cell recording provided preliminary evidence for opponent-color processing. Horizontal cells were only of the L type with both rod and cone inputs.
mesh_terms: D000818:Animals; D002452:Cell Count; D003623:Dark Adaptation; D004524:Eels / Q000502:physiology*; D004596:Electroretinography; D008027:Light; D008854:Microscopy, Electron; D010786:Photoreceptor Cells / Q000166:cytology; D012160:Retina / Q000166:cytology / Q000502:physiology*; D012168:Retinal Pigments / Q000502:physiology; D013057:Spectrum Analysis; D014785:Vision, Ocular / Q000502:physiology*
chemical_list: D012168:Retinal Pigments