Hello,
I am currently working on inserting pump mechanisms, specifically the Na-K ATPase, into a very simple neuron in order to map out the dynamics of the pump before we move to insert the mechanism into a more complex neuron.
Thus far, I have accomplished this by using the MultiCompartmentReaction function, but I have an interesting problem where the rate scheme that I am using is based purely on the concentrations of internal and external Na (as a form of simplification). This means that thus far, only the sodium concentrations are being affected by MultiCompartmentReaction, while the potassium is left out. This should be easy to fix because I could simply apply the molecular ratio of the Na-K exchange, but unfortunately I am unable to find a means to extract the sodium current of the MultiCompartmentReaction.
We are expecting other forms of Na-based exchange pumps such as Na-Ca to be involved in the larger model, so I also can't use ina as the basis. I'd really appreciate for any advice on this matter!
Adding a Rate to an Ion based on the flux of another Reaction function
Moderators: hines, wwlytton, ramcdougal
Re: Adding a Rate to an Ion based on the flux of another Reaction function
Hi,
If I have understood your question, you have something like;
Where `nai` and `nai` are rxd Species on an intracellular and extracellular region and `pump` is the rate of the Na/K-pump, that only depends on `nai` and `mem` is the membrane region.
To add a potassium current to the model you can add a second MultiCompartmentReaction reaction;
Where `ki` and `ko` are rxd Species on an intracellular and extracellular regions.
Or you could specify a single MultiCompartmentReaction to produce both currents;
If I have understood your question, you have something like;
Code: Select all
pump_current_na = rxd.MultiCompartmentReaction(nai, nao, 3.0*pump,
mass_action=False, membrane=mem,
membrane_flux=True)
To add a potassium current to the model you can add a second MultiCompartmentReaction reaction;
Code: Select all
pump_current_k = rxd.MultiCompartmentReaction(ki, ko, -2.0*pump,
mass_action=False, membrane=mem,
Membrane_flux=True)
Or you could specify a single MultiCompartmentReaction to produce both currents;
Code: Select all
pump = rxd.MultiCompartmentReaction(3*nai + 2*ko, 3*nao + 2*ki, pump,
mass_action=False, membrane=mem,
membrane_flux=True)