Electroretinographic evidence for a photopic system in the rat

It was found that the rat generates a bimodal b-wave amplitude by wavelength function and a bimodal luminosity curve with maxima at 510 and 570-600 nm. The secondary maximum is relatively unaffected by green and blue adaptation, but it is suppressed with red adaptation. It was also learned that b-wave implicit time varies as a function of wavelength with minima at 480 nm and 540 nm, and as a function of intensity with an apparent rod-cone break at 500 nm but not at 600 nm. A prominent x-wave, isolated from the b-wave, was observed at short wavelengths with a maximum amplitude at 480 nm. It was hypothesized that the rat possesses a photopic system, perhaps mediated by rhodopsin. Also, the presence of a long wavelength sensitive receptor pigment, which mediates the "red response", was postulated and the nature of such a receptor was discussed.