Dark-adaptation processes in the rhodopsin rods of the frog's retina

Donner, Karl Johan; Reuter, Tom

doi:10.1016/0042-6989(67)90023-5

Cited by 92 publications

(43 citation statements)

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“…2, continuous curves) on a linear scale of ordinate with a half-return time of 6 min (time-constant 8*7 min), and thus by a curve that describes the decay of metarhodopsin at the temperature of this experiment (13-14°C) (Donner & Reuter, 1967). But in the case of the results with the background the curve has been slid vertically upwards by 0-8 log units, i.e.…”

Section: Resultsmentioning

confidence: 98%

“…In the previous experiments (Figs. 2 and 3) and in our earlier work (Donner & Reuter, 1967) the effect of metarhodopsin has been evaluated for fully dark-adapted rods only, containing the full amount of rhodopsin except for the small fraction bleached. It is hence possible that the efficiency of metarhodopsin as a sensitivity-reducing agent varies with the rhodopsin content of the rods in some way.…”

Section: Resultsmentioning

confidence: 99%

“…This relation can be written (Donner & Reuter, 1967) as AJ = AJ0. 1Oat, (2) where the symbols are the same as in eqn.…”

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confidence: 99%

“…Metarhodopsins I and II are the first more stable photoproducts of rhodopsin and exist in a tautomeric equilibrium, which depends, among other factors, on temperature and pH (Matthews, Hubbard, Brown & Wald, 1963). Metarhodopsin shows an exponential decay in the retina, the time constant being about 6x5 min at + 150 in the rods of Finnish Rana temporaria (Donner & Reuter, 1967).…”

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confidence: 99%

“…METHODS Preparation and recording. The excised and opened eyes of common frogs (Rana temporaria from S. Finland) were dissected and treated according to our standard procedure (for a detailed description see Donner & Reuter, 1962 (Donner & Reuter, 1967). All the experiments reported here were carried out at a temperature of 13-14O C. When needed, rhodopsin measurements were carried out by extraction of the retina with digitonin (see Reuter, 1966).…”

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Visual adaptation of the rhodopsin rods in the frog's retina

Donner¹,

Reuter²

1968

The Journal of Physiology

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2. When such thresholds and the intensities of the background lights are expressed in terms of the number of quanta absorbed per unit time, it is found that three factors can be correlated with the thresholds measured in various states of light-and dark-adaptation: (i) the intensity of a steady background, (ii) the rate of regeneration of rhodopsin, and (iii) the amount of metarhodopsin II present in the rods.3. The threshold is found to be proportional both to the intensity of a background and to the rate of regeneration, whereas there is a linear relationship between the logarithm of the threshold and the amount of metarhodopsin II. 4. The presence of metarhodopsin elevates all thresholds, the absolute threshold, increment thresholds and the thresholds elevated by regenerating rhodopsin in the same way.5. The saturation of the rods at high background intensities is found to be correlated with the accumulation of significant amounts of metarhodopsin in the rods, caused by the bleaching effect of the background.6. The effect of metarhodopsin on the threshold is independent of the amount of rhodopsin present in the rods.7. The combined effect of all three factors can be expressed in a general formula, given as eqn. (7) on p. 74.8. A background not only reduces the signals from the rods illuminated, but also those from neighbouring unilluminated rods. This effect is rapidly decreased with increasing distance from rods covered by the background. This kind of lateral spread in the retina probably occurs also when the K. 0. DONNER AND TOM REUTER rate of regeneration affects the threshold. The effect of metarhodopsin, on the other hand, appears restricted to those receptors that contain this substance.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

“…This relation can be written (Donner & Reuter, 1967) as AJ = AJ0. 1Oat, (2) where the symbols are the same as in eqn.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%