Spectral characteristics of photoreceptors and horizontal cells in the retina of the Siberian sturgeon Acipenser baeri Brandt.

In the retina of Siberian sturgeon, three spectral classes of photoreceptors were identified by microspectrophotometry. These were rods, oil drop-containing and oil drop-free cones possessing P549, and oil drop-containing cones possessing P613 and P465. With intracellular recordings, rod-driven, cone-driven, and mixed horizontal cells of luminosity type were found, as well as color-opponent horizontal cells of, at least, 6 kinds. Biphasic R/G cells received hyperpolarizing input either from rods or from green cones; in R/B cells, it was from blue cones. Other three types comprised biphasic G/B (or Y/B), RG/B, and triphasic G/BR cells. So the Chondrostean retina has the color-processing circuitry common for all ray-finned fishes.