Figure 1.
Examples of experimental data and analysis.
The top panel displays voltage responses of an MWS-cone to 500 ms light stimuli. The intensity of the stimulus decreases from top to bottom as indicated by the relative intensity to the left of the traces. The stimulus wavelength increases from left to right as indicated below the traces. The bottom panel illustrates how cone responses were converted to spectral sensitivity functions using data from the same MWS-cone. Response amplitudes for different stimulus wavelengths were plotted against stimulus intensity. Subsequently Hill-relations were fit through data for each stimulus wavelength and the difference in half-maximal activation relative to the wavelength for which the cone was most sensitive (double arrow) was determined.
Table 1.
Properties of zebrafish cones.
Figure 2.
Action spectra of individual cells and averages per cone-type.
In the top four panels the relative sensitivity is plotted against the stimulus wavelength of individual cones grouped according to cone-type as indicated in the graph. The bottom panel displays the average spectral sensitivity for the different cone-types.
Table 2.
Parameters of photopigment template fits.
Figure 3.
Fits of pigment template to experimental data.
This figure displays the fits (solid lines) of the photopigment template [15] to the average experimental data per cone-type with the peak wavelength of the A1-based photopigment, the ratio between A1- and A2-based photopigment and the presence of the β-wave relative to the original photopigment template as free parameters. For comparison the spectral sensitivity functions of corresponding A1- (dashed lines) and A2-based (dotted lines) photopigments are also plotted. These were constructed according to the generic photopigment template in combination with their peak absorbance wavelength as measured in vitro [7]. The UV-cone action spectra deviates considerable from the UV template, presumably due to the small number of data points (top row, left). The action spectrum of the SWS cones was fully overlapped the SWS-2 adsorption spectrum (top row, right). For the MWS cones, both RH2–2 and RH2–3 templates were covering the MWS action spectrum, while RH2–1 and RH2–4 templates could not describe the action spectrum properly. Finally both LWS-1 and LWS-2 templates covered the LWS action spectrum.
Table 3.
Comparison of zebrafish cone spectral sensitivity data.