A Photoreceptor Model Considering Regulation of Ionic Homeostasis

Ito, Shinji; Sato, Kazuma; Himeno, Yukiko; Takeda, Yuichiro; Amano, Atsushi

doi:10.1016/j.bpj.2016.11.2871

Cited by 2 publications

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“…Earlier mathematical models have been proposed with significant ionic currents 9 – 11 ; however, they have some limitations for maintaining ion homeostasis, which is necessary for estimating energy consumption. In the current study, a novel mathematical model of the mouse rod was developed from our previous works 46 . We introduced mathematical formulas for ionic current activities combined with a phototransduction model.…”

Section: Methodsmentioning

confidence: 99%

Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors

Muangkram,

Himeno,

Amano

2023

Sci Rep

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To date, no effective treatment has been established for photoreceptor loss due to energy imbalances, but numerous therapeutic approaches have reported some success in slowing photoreceptor degeneration by downregulating energy demand. However, the detailed mechanisms remain unclear. This study aimed to clarify the composition of ATP consumption factors in photoreceptors in darkness and in light. We introduced mathematical formulas for ionic current activities combined with a phototransduction model to form a new mathematical model for estimating the energy expenditure of each ionic current. The proposed model included various ionic currents identified in mouse rods using a gene expression database incorporating an available electrophysiological recording of each specific gene. ATP was mainly consumed by Na+/K+-ATPase and plasma membrane Ca2+-ATPase pumps to remove excess Na+ and Ca2+. The rod consumed 7 $$\times$$ × 107 molecules of ATP s−1, where 65% was used to remove ions from the cyclic nucleotide-gated channel and 20% from the hyperpolarization-activated current in darkness. Increased light intensity raised the energy requirements of the complex phototransduction cascade mechanisms. Nevertheless, the overall energy consumption was less than that in darkness due to the significant reduction in ATPase activities, where the hyperpolarization-activated current proportion increased to 83%. A better understanding of energy demand/supply may provide an effective tool for investigating retinal pathophysiological changes and analyzing novel therapeutic treatments related to the energy consumption of photoreceptors.

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Section: Methodsmentioning

confidence: 99%

Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors

Muangkram,

Himeno,

Amano

2023

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Earlier mathematical models have been proposed with significant ionic currents [9][10][11]; however, they have some limitations for maintaining ion homeostasis, which is necessary for estimating energy consumption. In the current study, a novel mathematical model of the mouse rod was developed from our previous works [46]. We introduced mathematical formulas for ionic current activities combined with a phototransduction model.…”

Section: • Mathematical Modelmentioning

confidence: 99%

Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors

Muangkram

Himeno

Amano

2023

Preprint

Self Cite

View full text Add to dashboard Cite

To date, no effective treatment has been established for photoreceptor loss due to energy imbalances, but numerous therapeutic approaches have reported some success in slowing photoreceptor degeneration by downregulating energy demand. However, the detailed mechanisms remain unclear. This study aimed to clarify the composition of ATP consumption factors in photoreceptors in darkness and in light. We introduced mathematical formulas for ionic current activities combined with a phototransduction model to form a new mathematical model for estimating the energy expenditure of each ionic current. The proposed model included various ionic currents identified in mouse rods using a gene expression database incorporating an available electrophysiological recording of each specific gene. ATP was mainly consumed by Na+/K+-ATPase and plasma membrane Ca2+-ATPase pumps to remove excess Na+ and Ca2+. The rod consumed 7x107 molecules of ATP s− 1, where 65% was used to remove ions from the cyclic nucleotide-gated channel and 20% from the hyperpolarization-activated current in darkness. Increased light intensity raised the energy requirements of the complex phototransduction cascade mechanisms. Nevertheless, the overall energy consumption was less than that in darkness due to the significant reduction in ATPase activities, where the hyperpolarization-activated current proportion increased to 83%. A better understanding of energy demand/supply may provide an effective tool for investigating retinal pathophysiological changes and analyzing novel therapeutic treatments related to the energy consumption of photoreceptors.

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A Photoreceptor Model Considering Regulation of Ionic Homeostasis

Cited by 2 publications

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Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors

Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors

Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors

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