Figure 4.

Bleach-induced discrete transduction activity in single WT rods in darkness. A, Current recorded in darkness from a dark-adapted unbleached WT rod (dark-adapted), a rod 2 h after 1.4% rhodopsin bleach (bleached), an unbleached rod in 500 nm dim background light producing an estimated 0.14 R* s⁻¹ (dark-adapted + dim background light), and the averaged rod instrumental noise (n = 6) recorded in bright background light (instrumental noise). B, Averaged power spectra of the dark current recorded from WT rods that were dark-adapted (dark-adapted, black circles, n = 14), after a 1.4% rhodopsin bleach and incubation in darkness for 2 h (bleached, red squares, n = 16), or in bright background light (instrumental noise, n = 6). Dashed line is a spectrum from dark-adapted rods under dim background light (n = 4) as in A. C, Current recorded in darkness from a dark-adapted unbleached Gnat1^−/− rod (dark-adapted) and a Gnat1^−/− rod 2 h after 1.4% rhodopsin bleach (bleached). D, Averaged power spectra of the dark current recorded from Gnat1^−/− rods that were dark-adapted (dark-adapted, black circles, n = 10) or after a 1.4% rhodopsin bleach and incubation in darkness for 2 h (bleached, red squares, n = 10). Plots in B and D are shown as mean ± SEM.