Article Figures & Data
Figures
- Figure 1.
Comparison of G between a rod and a cone in carp. A, A carp rod was whole-cell voltage-clamped. B, A series of light flashes of varying intensities was given to obtain a family of light responses. The initial rising phases were fitted globally to Equation 4 using a unique value of G (red dotted traces). The flash intensities used were (from the dimmest): 8.2 × 10−8, 1.3 × 10−7, 2.6 × 10−7, and 8.2 × 10−6 fractional bleach. C, The flash intensity-response amplitude relation is plotted. Filled circles are the data points obtained in B and the solid curve indicates a Michaelis–Menten relation. D, Parameters determined by the fitting and measured Vos. E–H, Similar recordings were made in a carp cone, and the results are shown as in A–D. The flash intensities used in F were (from the dimmest): 1.3 × 10−6, 2.6 × 10−6, 8.1 × 10−6, and 8.1 × 10−5 fractional bleach. Each response shown in B and F is an average of at least two records.
- Figure 2.
Estimation of G in a bullfrog rod. A, A bullfrog rod was whole-cell voltage-clamped. B, A series of light flash of varying intensities was given to obtain a family of light responses. The initial rising phases were fitted globally to Equation 4 using a unique value of G (red dotted traces). The flash intensities were (from the dimmest): 1.3 × 10−8, 2.6 × 10−8, and 4.1 × 10−6 fractional bleach. Each response shown in B is an average of at least two records. C, The flash intensity-response amplitude relation. Filled circles are the data points obtained in B and the solid curve indicates a Michaelis–Menten relation. D, Parameters determined by the fitting and measured Vos.
- Figure 3.
Difference in the delay time between rods and cones in carp. Light responses were recorded by giving a light flash of 2.6 × 10−5 fractional bleach to a rod (black solid trace, an average of 21 records from 3 rods) or giving a light flash of 0.9–1.1 × 10−4 fractional bleach to a cone (red solid trace, an average of 5 records from 5 cones). Each of the records was fitted to Equation 4 (black and red dotted traces). The determined parameters in rods were G = 132 fL · sec−2 and teff = 10.3 ms, and those in cones were G = 36.3 fL · sec−2 and teff = 8.0 ms. The response evoked by a light flash of lower intensity (8.3 × 10−6 fractional bleach) in rods is also shown (gray trace, an average of 10 records from 4 rods), and the determined parameters were G = 104 fL · sec−2 and teff = 13.5 ms.
Tables
Carp Bullfrog Rod (n = 3) Rod (n = 5) Cone (n = 4) G (fL · sec−2) 91.2 ± 14.8 25.3 ± 3.2 81.0 ± 17.2 teff (msec) 16.2 ± 1.9 6.2 ± 0.7 17.7 ± 4.0 Vos (fL) 96.2 ± 20.1 100.8 ± 37.4 1890 ± 250 A (sec−2) 0.988 ± 0.283 0.283 ± 0.123 0.0431 ± 0.0101 I1/2 (fractional bleached/cell) 9.5 ± 3.5 × 10−8 4.5 ± 0.9 × 10−6 1.4 ± 0.4 × 10−8 Values are shown as mean ± SD. The number of the cells used is shown in parentheses.
