Document Type

Article

Embargo Period

1-1-1990

Publication Date

1-1-1990

Abstract

New visual pigments were formed with 4-hydroxy retinals in isolated vertebrate rod photoreceptors by exposing bleached rods from the tiger salamander, Ambystoma tigrinum, to lipid vesicles containing the analogues. Formation of physiologically active pigment was demonstrated by the restoration of sensitivity and by a shift of ~50 nm in the peak of both the visual pigment absorptance spectrum and rod spectral sensitivity spectrum from ~520 to ~470 nm for 11-cis 4-hydroxy retinal. Membrane current recordings from the inner segments of isolated rods revealed excess fluctuations in membrane current after formation of the new pigment in bleached cells or after exposure of unbleached cells to flashes in the presence of the analogue. The excess current fluctuations are similar to the fluctuations elicited by steady light producing a few discrete responses per second, a rate ~100 times greater than the normal rate of spontaneous events in darkness. These results suggest that analogues of retinal can produce alterations in the frequency of production of discrete responses in darkness in rod photoreceptors.

Journal

Biophysical Journal

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