Gerd Rosner’s research while affiliated with Ruhr University Bochum and other places

Adaptationsversuche mit quantengleichen monochromatischen Lichtern zeigen, da die Empfindlichkeit der Miegenretina 3 min nach monochromatischer Helladaptation annhernd proportional der Sehfarbstoffkonzentration in den Rezeptoren ist. Spektralphotometrisch wurde nachgewiesen, da whrend der Helladaptation sich photochemische Gleichgewichte zwischen dem Sehpigment P 490–500 und einem thermostabilen Folgefarbstoff M 550–560 einstellen.Adaptation with equal quanta monochromatic lights causes in the photoreceptors of the blow flyCalliphora three minutes after cessation in darkness an increase of threshold up to a level which is nearly proportional to the concentration of visual pigment P 490–500. Photometric measurements have shown that monochromatic illumination causes a photoequilibrium between visual pigment P 490–500 and its thermostable Metarhodopsin M 550–560.

The spectral sensitivity of the visual cells in the compound eye of the mothDeilephila elpenor was determined by electrophysiological mass recordings during exposure to monochromatic adapting light. Three types of receptors were identified. The receptors are maximally sensitive at about 350 nm (ultraviolet), 450 nm (violet), and 525 nm (green). The spectral sensitivity of the green receptors is identical to a nomogram for a rhodopsin with λmax at 525 nm. The spectral sensitivity of the other two receptors rather well agrees with nomograms for corresponding rhodopsins. The recordings indicate that the green receptors occur in larger number than the other receptors. The ultra-violet and violet receptors probably occur in about equal number. The sensitivity after monochromatic adapting illumination varies with the wavelength of the adapting light, but is not proportional to the spectral sensitivity of the receptors. The sensitivity is proportional to the concentration of visual pigment at photoequilibrium. The equilibrium is determined by the absorbance coefficients of the visual pigment and its photoproduct at each wavelength. The concentration of the visual pigment, and thereby the sensitivity, is maximal at about 450 nm, and minimal at wavelengths exceeding about 570 nm. The light from a clear sky keeps the relative concentration of visual pigment in the green receptors, and the relative sensitivity, at about 0.62. The pigment concentration in the ultra-violet receptors is about 0.8 to 0.9, and that in the violet receptors probably about 0.6. At low ambient light intensities a chemical regeneration of the visual pigments may cause an increase in sensitivity. At higher intensities the concentrations of the visual pigments remain constant. Due to the constant pigment concentrations the input signals from the receptors to the central nervous system contain unequivocal information about variations in intensity and spectral distribution of the stimulating light.