Spectral sensitivity of single retinula cells of the locust

Abstract

Intracellular electrode recording techniques were used to measure the responses of single visual cells in the locust to various intensities of monochromatic lights of wavelength 350 to 600 mμ. Response-energy curves, found for ten cells to be parallel at all wavelengths, were used to deduce the relative number of quanta required to evoke a constant response. The average response-energy curve from these ten cells was used in obtaining spectral sensitivity data for another ten short-lived cells, where only one response at each wavelength could be obtained.

Spectral sensitivity curves for all twenty cells showed a peak in the blue-violet (maximum about 430 mμ) region of the spectrum. In addition, all cells showed some green sensitivity (maximum about 515 mμ) but in different cells this varied from 15% to 100% of the blue-violet maximum for the cell. The magnitude of the errors is discussed.

The results are consistent with the hypothesis that two visual pigments which fit a Dartnall nomogram for rhodopsin are contributing, in various ratios, to the spectral sensitivity of every cell.