Hodgkin-Huxley model succeeded in recapitulating the behavior of ions by using a circuit model.
However, many thesis use a semi-experimental method to describe the gating variable:alpha and beta. Thus I'm wondering if we can make a simulator by exploiting the knowledge of detailed structual properties of channels and physics.
In other words, I want to calculate the gating variable g(V) (which appear in the equation:I=g(V)*(B-E)) without curve-fitting the raw data.
Is there anyone trying to do so? or is it already developed?
I have studied that certain aminos (e.g. tryptophan) in the ion channel back-bone are responsible for regulating ion current through the channel by "changing" their shape. At the molecular level, the electrostatic potential associated with these geometric shape changes influences the rate of change of ion flow. Modeling electrostatic potential as a function ensembles of amino geometric dynamics would be useful.
Brett Sims Thank you very much. I have briefly read your paper "A DEVELOPMENT ON MOLECULAR-LEVEL TIME AND VOLTAGE DEPENDENT ION FLUX MODELS", and this approach can be generally used to model the behavior of channels with changes in time and voltage, in my opinion.
Dear Tomohide,
you risk wasting your time big time. Please look here at the RG platform for the work of Thomas Heimburg on membrane capacitance. remember that in the HH electrical equivalent model, it is a constant. Also look at the work of Prof. Hirohisa Tamagawa, excellent critical work on such model from another angle, befor you comit time and energy in your quest. another heretical must is the work of Gilbert Ling on the pump.
just one more name: Ichigi Tasaki and his membrane model, I am a big fan!
Vera Maura Fernandes de Lima Sorry for my late reply and thank you for answering my question. I'll have a look at your recommendations.
You did answer in your own time, that is fine here at RG
Tomohide R. Sato : Your equation ("I=g(V)*(B-E))") seems too easy. If that's all you want to simulate, it can be done in five minutes. Do you have any more precise information?
Mark Sitkowski I think that simply calculating "g" part is not so easy because in order to model conductance of an ion channel, we need to consider structural data of it(or at least, structure of voltage-sensing domain). Thus calculating "g" will require a lot of computational power.
Mark Sitkowski Actually I don't have the equation. In other words, finding an equation which connects structure of the ion channel and conductance itself is a problem, and if it is finded, then all I have to do is to solve with computers.
In BEELER AND REUTER's paper "RECONSTRUCTION OF THE ACTION POTENTIAL OF VENTRICULAR MYOCARDIAL FIBRES" (J. Phyaiol. (1977), 268, pp. 177-210); the equations, details, and parameters for the "gating" variables are explicitly written. In my 2002 PhD work, I used the "BEELER-REUTER Equations" to compute magnetic field-strength profiles for traveling action potentials in 1-dimensional neural and cardiac tissue.
The equations on page 181 of Beeler & Reuter's paper are easy to model. The relationships between them aren't clear to me, as this isn't my field, but I'll try reading the paper a bit more thoroughly.
Mark Sitkowski Thank you. Beeler&Reuter's paper was one of my interests, and I'll read it thoroughly, too.
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