Spontaneous voltage fluctuations in retinal cones and bipolar cells

TRIFONOV1 and others have suggested that vertebrate rods and cones release transmitter continuously in the dark and that the effect of light is to suppress this release by making the inside of the cell more negative. On this hypothesis the bipolar cells, which receive information from cones, should be electrically noisy in the dark, because of random fluctuations in the release of cone transmitter, and relatively quiet in the light when the release of transmitter is suppressed2.