Rhodopsin and the visual process

Ostroy, Sanford E.

doi:10.1016/0304-4173(77)90004-0

Cited by 90 publications

(39 citation statements)

References 152 publications

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“…The flaw in the cGMP scheme as the only mechanism of visual transduction is that it can hardly explain the fast rate of photoreceptor cell excitation developing within 5 ms if light intensity is sufficiently high [13,14]. The studies performed on living perfused retinas showed that much longer illumination was required to lower substantially the cGMP level [8,15].…”

Section: The Cgmp Pathwaymentioning

confidence: 99%

The dual role of rhodopsin in vision: light‐driven charge translocation and formation of long‐lived photoproducts

Skulachev

1982

FEBS Letters

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Section: The Cgmp Pathwaymentioning

confidence: 99%

The dual role of rhodopsin in vision: light‐driven charge translocation and formation of long‐lived photoproducts

Skulachev

1982

FEBS Letters

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“…In bacteriorhodopsin, this process of 'bleaching' takes about 50 ps, in animals it develops slower, in the millisecond scale. There is an indication that protonation of a protonaccepting group, X, of visual rhodopsin precedes the Schiffbase deprotonation [38]. Bleached bacteriorhodopsin converts back to the original form absorbing at 570 nm (tip about 10 ms), whereas bleached animal rhodopsin (called metarhodopsin 11) splits irreversibly and slowly (in minute timescale), mainly via metarhodopsin 111, into opsin and all-trans retinal.…”

Section: Similarity N J Animal and Bacterial Rhodopsinsmentioning

confidence: 99%

“…In both metarhodopsin I and the bacteriorhodopsin absorbing at 550 nm, the Schiff basc is still protonated. The next step is its deprotonation accompanied by a strong spectral shift to short wavelengths (to 412 nm for bacterial and to 380 nm for animal rhodopsin) [38]. In bacteriorhodopsin, this process of 'bleaching' takes about 50 ps, in animals it develops slower, in the millisecond scale.…”

Section: Similarity N J Animal and Bacterial Rhodopsinsmentioning

confidence: 99%

“…In any case, the main electrogenic phases are coupled with conversion of metarhodopsin I -+ metarhodopsin 11. It is this step that is known to be accompanied by major conformational changes in the rhodopsin molecule [38].…”

Section: Mechanism Of the Rhodopsin Photoelectric Responsementioning

confidence: 99%

“…There are many indications of reversible protonation and deprotonation processes accompanying a photocycle of visual rhodopsin (for review, see [38]). Lewis [39], summarizing several bodies of indirect evidence, even suggested several years ago a light-dependent H + translocation from the outside to the inside of photoreceptor discs.…”

Section: Similarity N J Animal and Bacterial Rhodopsinsmentioning

confidence: 99%

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Fast Stages of Photoelectric Processes in Biological Membranes

Drachev¹,

Skulachev²,

Kaulen³

et al. 1981

European Journal of Biochemistry

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The functioning of visual rhodopsin as a photoelectric generator has been demonstrated with a direct method. Photoreceptor discs were incorporated into a phospholipid-impregnated collodion film. Illumination' of the resulting system with continuous light was found to induce formation of a n electric potential (the disc-free side positive) that was measured with two electrodes separated by the film. A photopotential exceeding 40 mV was shown. It dissipated before the light source was switched off. A 15 ns 530-nm laser flash induced the formation of a photopotential of up to 35 mV whose appearance was preceded with a small oppositely directed electrogenic phase. This 'negative' photoresponse took less than 200 ns. The 'positive' photoresponse was composed of at least two phases (tllz about 500 ps and several milliseconds). The latter was shown to correlated with formation of metarhodopsin 11.A 347-nm laser flash added after a 530-nm flash resulted in a photoelectric effect similar to that initiated by 530-nm flash but of opposite direction. The 347-nni rcsponse was completely abolished by hydroxylamine preventing the accumulation of metarhodopsin 11. The response at 530 nm proved to be hydroxylamine-resistant. Both the amplitude and the decay time of the flash-induced potential were maximal in the response to the first flash, each subsequent flash being less effective than the preceding one. Flashes were found to c a w acceleration of the photopotential decay. The latter effect proved to be due to a increase of membrane conductance that dcveloped faster than in 50 ms. Addition of 1 1-cis retinal after illumination improved the amplitude of the photoresponse but not the conductance. The light-induced increase in conductance was insensitive to hydroxylamine.It is suggested that a function of visual rhodopsin consists in generating a potential difference across the photoreceptor disc membrane which responds with a increase in membrane permeability to a rise of the membrane potential. A possible role of an electric breack-down of the membrane, induced by the rhodopsin-generated local or partially delocalized electric field has been discussed.Chronologically, the first idea about the biological function of bacteriorhodopsin was photoreception [ I , 21. Such an assumption seemed to be reasonable since it was known that phototaxis is inherent in Halobacteviu containing bacteriorhodopsin. However, the whole development of the bacteriorhodopsin study clearly showed that this pigment is a lightdependent H + pump. Recently in this group it was revcaled that the role of bacteriorhodopsin in the positive phototaxis is very indirect being confined to generation of ADH the level of which is monitored by an intracellular A&-measuring system producing a signal for taxis [3].As to animal (visual) rhodopsin, its direct involvement in photoreception in unquestionable. The problem is how rhodopsin fulfils the photoreceptor function. In this paper we would like to describe experiments indicating that visual rhodopsin, like its bacteria...

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The Photochemistry of Rhodopsins

Ottolenghi

1980

Advances in Photochemistry

161

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Rhodopsin and the visual process

Cited by 90 publications

References 152 publications

The dual role of rhodopsin in vision: light‐driven charge translocation and formation of long‐lived photoproducts

The dual role of rhodopsin in vision: light‐driven charge translocation and formation of long‐lived photoproducts

Fast Stages of Photoelectric Processes in Biological Membranes

The Photochemistry of Rhodopsins

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