A theoretical study on heat production in squid giant axon

Nogueira, R. de A.; Garcia, E.A. Conde

doi:10.1016/0022-5193(83)90400-9

Cited by 9 publications

(4 citation statements)

References 10 publications

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“…Note that the actual intracellular potential with respect to the extracellular potential is given by V’ + V R . We considered two types of Joule heat (nW/cm 2 ) in the nerve cell: heat due to the ion movement across the cell membrane through channels ( Q 1 ) (nW/cm 2 ) and heat due to ion movement along the longitudinal axis of the nerve ( Q 2 ) (nW/cm 2 ) according to ref [ 14 ] with modification. By Eq (5), we calculated Q 1 as,…”

Section: Methodsmentioning

confidence: 99%

“…We set up the coupled differential equations according to the H-H model with parameter values for a squid giant axon (Supplementary Text S2; Supplementary Tables S2 and S3) and reproduced on a computer the results of the numerical solutions of the membrane potential (Figure 3B) and the ion currents for Na + , K + , and leak ions (Figure 3C). Subsequently, we used the numerical solutions to examine two types of Joule heat production (Supplementary Text S2) [14]. One type of the Joule heat Q1 was attributed to ion currents passing through the channel proteins on the cellular membrane (Eq (10); Figure 3A).…”

Section: Heat From a Nerve Cellmentioning

confidence: 99%

“…Additionally, a theoretical calculation of the Joule heating from a nerve fiber based upon the H-H model was previously performed by Nogueira and Conde Garcia [14], but they computed the heat of channel currents in a form of Gi•(V′ -Vi) 2 , where Gi and Vi are an ion conductivity and the equilibrium potential, respectively, for an ion species i. However, in our study, we corrected their theory as explained in the Section Joule Heating Involving Ion Flow and Electric Potential so that the ion current Gi•(V′ -Vi) was multiplied by the membrane potential (V′ + VR), which the ion particles experience when they move from one side of a membrane to the other side through a channel.…”

Section: E200030_7mentioning

confidence: 99%

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Joule heating involving ion currents through channel proteins

Wazawa

Nagai

2023

BIOPHYSICS

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Ion currents associated with channel proteins in the presence of membrane potential are ubiquitous in cellular and organelle membranes. When an ion current occurs through a channel protein, Joule heating should occur. However, this Joule heating seems to have been largely overlooked in biology. Here we show theoretical investigation of Joule heating involving channel proteins in biological processes. We used electrochemical potential to derive the Joule’s law for an ion current through an ion transport protein in the presence of membrane potential, and we suggest that heat production and absorption can occur. Simulation of temperature distribution around a single channel protein with the Joule heating revealed that the temperature increase was as small as <10 –3 K, although an ensemble of channel proteins was suggested to exhibit a noticeable temperature increase. Thereby, we theoretically investigated the Joule heating of systems containing ensembles of channel proteins. Nerve is known to undergo rapid heat production followed by heat absorption during the action potential, and our simulation of Joule heating for a squid giant axon combined with the Hodgkin-Huxley model successfully reproduced the feature of the heat. Furthermore, we extended the theory of Joule heating to uncoupling protein 1 (UCP1), a solute carrier family transporter, which is important to the non-shivering thermogenesis in brown adipose tissue mitochondria (BATM). Our calculations showed that the Joule heat involving UCP1 was comparable to the literature calorimetry data of BATM. Joule heating of ion transport proteins is likely to be one of important mechanisms of cellular thermogenesis.

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Section: Methodsmentioning

confidence: 99%

Section: Heat From a Nerve Cellmentioning

confidence: 99%

Section: E200030_7mentioning

confidence: 99%

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Joule heating involving ion currents through channel proteins

Wazawa

Nagai

2023

BIOPHYSICS

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“…It is however estimated [42] that about 90% of the total heat is liberated after the stimulus ie the AP is over. The general understanding is that the heat generated during the fast period may be the result of the Joule heating [40,43] or capacitative processes [38,41,44] and the process of reabsorption may be due to endothermic chemical reactions [39].…”

Section: On Physical Backgroundmentioning

confidence: 99%

On physical background of nerve pulse propagation: heat and energy

Engelbrecht,

Tamm,

Peets

2020

Preprint

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Recent studies have revealed the complex structure of nerve signals in axons. Besides the electrical signal, mechanical and thermal effects are also detected in many experimental studies. In this paper, the mathematical models of heat generation are analysed within the framework of a general model derived earlier by the authors. The main mechanisms of the heat generation are seemingly the Joule heating and endo-and exothermic reactions. The concept of internal variables permits to model the heat relaxation typical to these reactions. The general energy balance of the whole signal is analysed based on physical mechanisms responsible for emerging the components of a signal. Some open questions are listed for further studies.

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