Single photon transduction in Limulus photoreceptors and the Borsellino-Fuortes model

Goldring, Marc; Lisman, John

doi:10.1109/tsmc.1983.6313066

Cited by 7 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When elementary responses are considered, "it is essential to take into account the stochastic fluctuations of the response in addition to the fluctuations of the stimulus." We do not agree with the analytical results of these two authors (Borsellino and Fuortes, 1968a,b), which have been shown to be in error (Goldring and Lisman, 1983), but we take their view of the stochastic features of transduction processes as a basic start.…”

Section: Introductioncontrasting

confidence: 89%

“…28A in Borsellino and Fuortes (1968a), with slight changes of symbols.) Although this result has been shown to be incorrect (Goldring and Lisman, 1983), the Borsellino-Fuortes model is still considered valid. In this equation, the first member is the probability of having n molecules at time t (after an arbitrary number of amplifying steps), whereas m(t) is the average number expected at time t. Equation 12 states that the distribution of the number of molecules during a chemical amplification is a Poisson distribution and implies that the standard deviation is at each time t the square root of the average number expected at that time, so that the higher the amplification, the lower the variation coefficient.…”

Section: Computer Simulations On the Starting Modelmentioning

confidence: 99%

“…Note also that the standard deviation according to Borsellino and Fuortes (1968a) takes on the same value for equal values of the average on both the increasing and the decreasing part of the time course, which does not occur in the simulation. The correct equation obtained by Goldring and Lisman (1983) (instead of Eq. 12) is too cumbersome, however, to be used straightforwardly.…”

Section: Computer Simulations On the Starting Modelmentioning

confidence: 99%

“…By the same token, when the first few steps in the cascade do not amplify (G = 1) and are followed by an amplifying step, a similar effect on the dose-response curve is expected. This type of cascade was adopted by Goldring and Lisman (1983) in a simulation of quantum bump kinetics of the Limulus ventral receptors. However, we must take into account that changing the time constants of the pigment photocycle produces a shift in the experimental dose-response curves without affecting their slope (Takahashi et al, 1992).…”

Section: Models With a Cascade Of Amplifying Loopsmentioning

confidence: 99%

See 3 more Smart Citations

Photoreceptor sensitivity and the shot noise of chemical processes

Petracchi

Cercignani

Lucia

1996

Biophysical Journal

View full text Add to dashboard Cite

The general modeling of dose-response curves to very low stimuli in a photosensory-effector system is critically reshaped starting from basic assumptions on the fluctuations of chemical signals inside the receptor cell, which add to those of the stimulus itself, both arising from their granular (or quantal) structure. We have shown, both through the analytical treatment of a simple kinetic scheme and by means of Monte Carlo simulations of the same, that shot noise arising from chemical transduction ("chemical shot noise") contributes considerably to the output noise of the receptor-effector system, thus affecting both the shape and the abscissa shift of dose-response curves under these conditions; the latter phenomenon has indeed been reported in Halobacterium halobium. After evaluating the general properties of a single-step amplifying mechanism, the effects of introducing several low-amplifying steps in cascade were investigated briefly. The results obtained were qualitatively and quantitatively at variance from those of earlier models on the same phenomenon, and the discrepancies are discussed in order to highlight the fundamental contribution of chemical shot noise to the response of any kind of sensory system to very low stimuli.

show abstract

Section: Introductioncontrasting

confidence: 89%

Section: Computer Simulations On the Starting Modelmentioning

confidence: 99%

Section: Computer Simulations On the Starting Modelmentioning

confidence: 99%

Section: Models With a Cascade Of Amplifying Loopsmentioning

confidence: 99%

See 2 more Smart Citations

Photoreceptor sensitivity and the shot noise of chemical processes

Petracchi

Cercignani

Lucia

1996

Biophysical Journal

View full text Add to dashboard Cite

show abstract

“…Although, the influence of intracellular calcium on the early phase of the current is clearly demonstrated, the integrated cascade model of seems to be inadequate. Namely, models in which the latency and amplification are assumed to be due to separated processes (see below) fit the current far better (Goldring & Lisman, 1983;Keiper et al 1984;Schnakenberg & Keiper, 1986;Kraemer et al 1989;Schnakenberg, 1989). suggested that the facilitation and the supralinearity of the light-intensity dependence of the receptor current are due to the same molecular mechanism.…”

Section: Models Of Excitationmentioning

confidence: 99%

Biophysical processes in invertebrate photoreceptors: recent progress and a critical overview based on Limulus photoreceptors

Nagy

1991

Quart. Rev. Biophys.

View full text Add to dashboard Cite

Limulus ventral nerve photoreceptor, a classical preparation for the study the phototransduction in invertebrate eyes, seems to have a very complex mechanism to transform light energy into a physiological signal. Although the main function of the photoreceptor is to change the membrane conductance according to the illumination, the cell has voltage-activated conductances as well. The voltage-gated conductances are matched to the light-activated ones in the sense that they make the function of the cell more efficient. The complex mechanism of phototransduction and the presence of four different voltage-gated conductance in Limulus ventral nerve photoreceptors indicate that these cells are far less differentiated than the photoreceptor cells of vertebrates. Indications accumulated in recent years support the view that the ventral photoreceptor of Limulus has different light-activated macroscopic current components, ion channels and terminal transmitters. After conclusions from macroscopic current measurements (Payne, 1986; Payne et al. 1986 a, b), direct evidence was presented by single-channel (Nagy & Stieve, 1990 a, b; Nagy, 1990 a, b) and macroscopic current measurements (Deckert et al. 1991 a, b) for three different light-activated conductances. It has been shown that two of these conductances are stimulated by two different excitation mechanisms. The two mechanisms, having different kinetics, release probably two different transmitters. One of them might be the cGMP (Johnson et al. 1986), the other one the calcium ion (Payne et al. 1986 a, b). However, the biochemical processes which link the rhodopsin molecules and the ion channels are not known. The unknown chemical details of the phototransduction result in a delay for the mathematical description of the biophysical mechanisms. More biochemical details are known about the adaptation mechanism. It was found that inositol 1,4,5-trisphosphate is a messenger for the release of calcium ions from the intracellular stores and that calcium ions are the messengers for adaptation (Payne et al. 1986 b; Payne & Fein, 1987). Concerning the mechanism of calcium release, it was revealed that a negative feedback acts on the enzyme cascade to regulate the internal calcium level and to protect the stores against complete emptying (Payne et al. 1988, 1990). Calcium ions also play an important role in the excitation mechanism. (a) In [Ca2+]i-depleted cells the light-induced current was increased after intracellular Ca2+ injection, suggesting that calcium is necessary for the transduction mechanism (Bolsover & Brown, 1985).(ABSTRACT TRUNCATED AT 400 WORDS)

show abstract

The characteristics of chemically induced noise inMusca photoreceptors

Minke¹,

Stephenson

1985

J. Comp. Physiol.

View full text Add to dashboard Cite

Single photon transduction in Limulus photoreceptors and the Borsellino-Fuortes model

Cited by 7 publications

References 0 publications

Photoreceptor sensitivity and the shot noise of chemical processes

Photoreceptor sensitivity and the shot noise of chemical processes

Biophysical processes in invertebrate photoreceptors: recent progress and a critical overview based on Limulus photoreceptors

The characteristics of chemically induced noise inMusca photoreceptors

Contact Info

Product

Resources

About