how can I get the parameters for variables in H-H equation?

[neuronuser]

Hi, everyone, I have another problem. I have read the paper by A. L. Hodgkin and A. F. Huxley in 1952, but still couldn't get a clear answer. From my experiment, I got the steady state activation and inactivation curve of sodium channel, and estimated the τm and τh by Hodgkin-Huxley type fit in Pulsefit software. I wonder how to calculate the parameters in the equation of αm, βm, αh, βh or infm, infh (is infm equal to m∞ in Hodgkin’s paper?) which are needed to build a channel in channel builder. For example, in the channel builder infm=A/(1+exp(-k*(d-v))), in the Boltzman equation which is used to fit the activation curve G = Gmin + (Gmax -Gmin)/(1 + exp((V1/2 - V)/k)). What is the relationship between these constant? d=- V1/2? Or something else? I’m looking forward to a reply from you. Thanks!

[ted]

The HH model involves mathematical expressions that can be rearranged in many different ways, but which are all equivalent to each other after some algebraic manipulation. This is an excellent learning moment, which offers you the opportunity to answer your own questions. Write down the equations that you find in the paper you cite, look for similar equations in the Channel Builder, and see if, by algebraic rearrangement, you can demonstrate the underlying identities.

is infm equal to m∞ in Hodgkin’s paper?

The two are one and the same.

I am not familiar with Pulsefit or the form of the HH equations that it uses, but if this is an example
G = Gmin + (Gmax -Gmin)/(1 + exp((V1/2 - V)/k))
then Pulsefit deviates from the "classical HH form." Pulsefit's documentation should contain explanations of such deviations. If it does not, its users are expected to fall back on their own resources. The first steps in reducing the particular example you cite to the classical HH form are to set Gmin to 0, replace Gmax by gbar, and replace G by ginf or "steady state g".

[neuronuser]

Thank you, Ted. I will try.