Xenbase Image ID: 122277

Figure 1. . Light responses of larval and adult Xenopus rod photoreceptors. (A) Isolated rod photoreceptors from a stage 48 tadpole (left) and froglet (right) in the recording chamber following retinal dissociation. Typically rod outer segments (ROS) of froglet rods were three times the length of ROS in young tadpole rods. ROS diameters of both young tadpole and froglet rods used for this study had reached mature dimensions of 6–7 μm. Bar, 10 μm. (B) Photocurrents recorded from a tadpole rod using the suction electrode technique. Photocurrents were elicited by a series of 520-nm flashes, 20 ms in duration of the intensities 0.32, 1.1, 4.9, 12.0, 54.0, 123.7, 514.3 hυ/μm2. Recordings of dim flashes are averages of eight responses, recordings of saturating flashes are averages of two responses. (C) Photocurrents recorded from a froglet rod stimulated as in B. Relative to tadpole rods, the saturating current tripled in magnitude and the responses were faster at onset and recovery. (D) Dependence of saturating current on rod length. The plot shows averaged values grouped according to stage of development: young tadpoles corresponding to stages 48–50, limbbud tadpoles corresponding to stages 54–56, and froglets. Double error bars indicate SEM. On average, froglet ROS were three times as long as ROS of young tadpoles. The saturating currents grew in the same proportion, suggesting that the density of the currents (0.3 pA/μm) does not change with development. Current density was estimated from the slope of the line interpolating the data and passing through the origin (R2 > 0.99). Image published in: Solessio E et al. (2004) Copyright © 2004, The Rockefeller University Press. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View

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