title: Phototransduction early steps model based on Beer-Lambert optical law.
abstract: The amount of available rhodopsin on the photoreceptor outer segment and its change over time is not considered in classic models of phototransduction. Thus, those models do not take into account the absorptance variation of the outer segment under different brightness conditions. The relationship between the light absorbed by a medium and its absorptance is well described by the Beer-Lambert law. This newly proposed model implements the absorptance variation phenomenon in a set of equations that admit photons per second as input and results in active rhodopsins per second as output. This study compares the classic model of phototransduction developed by Forti et al. (1989) to this new model by using different light stimuli to measure active rhodopsin and photocurrent. The results show a linear relationship between light stimulus and active rhodopsin in the Forti model and an exponential saturation in the new model. Further, photocurrent values have shown that the new model behaves equivalently to the experimental and theoretical data as published by Forti in dark-adapted rods, but fits significantly better under light-adapted conditions. The new model successfully introduced a physics optical law to the standard model of phototransduction adding a new processing layer that had not been mathematically implemented before. In addition, it describes the physiological concept of saturation and delivers outputs in concordance to input magnitudes.
authors.affiliation: Group of Artificial Intelligence and Robotics, Universidad Tecnolgica Nacional, Av. Medrano 951, Capital Federal, Argentina. Electronic address: ezequielsalido@gmail.com.
authors.forename: Ezequiel M
authors.initials: EM
authors.lastname: Salido
authors.affiliation: Group of Artificial Intelligence and Robotics, Universidad Tecnolgica Nacional, Av. Medrano 951, Capital Federal, Argentina. Electronic address: leonardoservalli@gmail.com.
authors.forename: Leonardo N
authors.initials: LN
authors.lastname: Servalli
authors.affiliation: Group of Artificial Intelligence and Robotics, Universidad Tecnolgica Nacional, Av. Medrano 951, Capital Federal, Argentina.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Gomez
authors.affiliation: Group of Artificial Intelligence and Robotics, Universidad Tecnolgica Nacional, Av. Medrano 951, Capital Federal, Argentina.
authors.forename: Claudio
authors.initials: C
authors.lastname: Verrastro
mesh_terms: D000818:Animals; D003198:Computer Simulation; D007700:Kinetics; D008027:Light; D055537:Light Signal Transduction / Q000502:physiology*; D008962:Models, Theoretical; D010775:Photic Stimulation; D015203:Reproducibility of Results; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D012243:Rhodopsin / Q000378:metabolism*; D014785:Vision, Ocular / Q000502:physiology*
chemical_list: D012243:Rhodopsin
keywords: Absorptance; Beer Lambert law; Mathematical model; Phototransduction; Rhodopsin