Re-modeling &lt;em&gt;Chara&lt;/em&gt; action potential: I. from Thiel model of Ca&lt;sup&gt;2+&lt;/sup&gt;transient to action potential form

Beilby, Mary J.; Khazaaly, Sabah Al

doi:10.3934/biophy.2016.3.431

Cited by 26 publications

(23 citation statements)

References 17 publications

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“…As for the total charge transport concerning one living cell, several research groups have already reported the analysis based on the electrocoupling of plural ion transports and/or electron transport . They succeeded in an explanation of action mechanism on the biological functions such as generation of action potentials, oscillations of membrane potentials, etc .…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Interpretation of Propagation of the Change in the Membrane Potential Using the Goldman‐Hodgkin‐Katz Equation

2017

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Nerve conduction has been frequently explained by the Hodgkin‐Huxley equation based on the flow of K+ and Na+ across the cell membrane. By considering the relation between the membrane potential and the membrane current based on the Goldman‐Hodgkin‐Katz equation, it becomes clear that the conventional analysis using the voltage‐clamp method is not correct and that the hyperpolarization condition is artificially made. Taking into account the channel functions and the electronic properties, we suggested a new propagation mechanism. When the nerve cell is excited by an external stimulus, the ligand‐gated channels at the synapse serve as an electric power source to propagate the change in the membrane potential to the synapse terminal along the axon and the voltage‐gated channels at the axon locally assist the directional propagation along the axon.

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Section: Resultsmentioning

confidence: 99%

Electrochemical Interpretation of Propagation of the Change in the Membrane Potential Using the Goldman‐Hodgkin‐Katz Equation

2017

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“…In the Thiel-Beilby model (Beilby and Al Khazaaly, 2016, 2017) the excitation is initiated by an input of excitable amount of IP 3 , I 0 , into the cytoplasm. The IP 3 concentration, I, then decays with time t and the time constant determined experimentally by repetitive stimulations (Wacke et al, 2003): eqnarrayright center leftI=I0e-0.2t…”

Section: Methodsmentioning

confidence: 99%

“…We became interested in the action potential (AP) form of Nitellopsis , as Shepherd et al (2008) found that spontaneous APs contributed to saline pathology of Chara australis by depleting the cells of K + and Cl − . In this salt sensitive Characeae, a mild salinity of 50 mM NaCl had a profound effect on the AP shape and extended the AP duration from 2 to up to 60 s. The AP form was fitted by Thiel-Beilby model (Beilby and Al Khazaaly, 2016, 2017), which suggested that the re-sequestering of Ca 2+ into internal stores was affected by salinity, leading to longer opening of the Ca 2+ -activated Cl − channels. As Nitellopsis survives in 20–50 mM NaCl media, our present experiments set out to discover if the AP form is more resistant to salinity stress.…”

Section: Introductionmentioning

confidence: 94%

“…Salinity stress is critical for plants and impacts on excitability. The AP of brackish Characeae Nitellopsis obtusa , obtained in artificial pond water (APW) and under osmotic stress of 90 or 180 mM sorbitol APW or saline stress of 50 or 100 mM NaCl APW, were simulated by the Thiel-Beilby model (Beilby and Al Khazaaly, 2016). The model is based on a paradigm from animal systems, featuring the second messenger inositol 1,4,5-triphosphate (IP 3 ) mediating the opening of Ca 2+ channels on internal stores.…”

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Modeling the Action Potential in Characeae Nitellopsis obtusa: Effect of Saline Stress

et al. 2019

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Action potentials (AP) of characean cells were the first electrical transients identified in plants. APs provide information about plethora of environmental cues. Salinity stress is critical for plants and impacts on excitability. The AP of brackish Characeae Nitellopsis obtusa , obtained in artificial pond water (APW) and under osmotic stress of 90 or 180 mM sorbitol APW or saline stress of 50 or 100 mM NaCl APW, were simulated by the Thiel-Beilby model (Beilby and Al Khazaaly, 2016 ). The model is based on a paradigm from animal systems, featuring the second messenger inositol 1,4,5-triphosphate (IP 3 ) mediating the opening of Ca 2+ channels on internal stores. In plants the IP 3 receptors have not been identified, so other second messengers might translate the threshold plasma membrane depolarization to Ca 2+ release. The increased Ca 2+ concentration in the cytoplasm activates Cl − channels, which lead to the depolarizing phase of the AP. The repolarization to normal resting potential difference (PD) results from the Ca 2+ being re-sequestered by the Ca 2+ pumps, the closure of the Cl − channels, efflux of K + through the depolarization-activated outward rectifier channels and the continuing activity of the proton pump. The Nitellopsis AP form is longer in APW compared to that of Chara , with more gradual repolarization. The tonoplast component of the AP is larger than that in Chara australis . The plasma membrane AP is prolonged by the exposure to saline to a “rectangular” shape, similar to that in Chara . However, the changes are more gradual, allowing more insight into the mechanism of the process. It is possible that the cells recover the original AP form after prolonged exposure to brackish conditions. Some cells experience tonoplast APs only. As in Chara , the proton pump is transiently inhibited by the high cytoplasmic Ca 2+ and gradually declines in saline media. However, if the cells are very hyperpolarized at the start of the experiment, the pump inhibition both by the AP and by the saline medium is mitigated. The model parameters and their changes with salinity are comparable to those in Chara .

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“…where nptq denotes the state of the complete system in Eq. (19) and xnp8qy is the mean state of system at time 8 due to constant input c. Similarly, by using standard results on the LTI system, the cross spectral density Ψ xe pωq has the following property:…”

Section: A Mutual Informationmentioning

confidence: 99%

Communication and Information Theory of Single Action Potential Signals in Plants

Awan

Adve

Wallbridge³

et al. 2019

IEEE Trans.on Nanobioscience

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Many plants, such as Mimosa pudica (the "sensitive plant"), employ electrochemical signals known as action potentials (APs) for rapid intercellular communication. In this paper, we consider a reaction-diffusion model of individual AP signals to analyze APs from a communication-and information-theoretic perspective. We use concepts from molecular communication to explain the underlying process of information transfer in a plant for a single AP pulse that is shared with one or more receiver cells. We also use the chemical Langevin equation to accommodate the deterministic as well as stochastic component of the system. Finally we present an information-theoretic analysis of single action potentials, obtaining achievable information rates for these signals. We show that, in general, the presence of an AP signal can increase the mutual information and information propagation speed among neighboring cells with receivers in different settings.

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Re-modeling <em>Chara</em> action potential: I. from Thiel model of Ca<sup>2+</sup>transient to action potential form

Cited by 26 publications

References 17 publications

Electrochemical Interpretation of Propagation of the Change in the Membrane Potential Using the Goldman‐Hodgkin‐Katz Equation

Electrochemical Interpretation of Propagation of the Change in the Membrane Potential Using the Goldman‐Hodgkin‐Katz Equation

Modeling the Action Potential in Characeae Nitellopsis obtusa: Effect of Saline Stress

Communication and Information Theory of Single Action Potential Signals in Plants

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