intracellular K depletion and extracellular K accumulation
Posted: Sat Apr 10, 2010 3:00 am
Hi ,
I am trying to create a mechanism that reads the potassium current ik and computes the values of ki and ko. What i also require is that ik should also be dependent on the newly modified values of ik and ko. The model that I have in mind is a single compartment soma(with a certain initial potassium concentration ki_initial) enveloped by a fixed volume of extracellular space (again with a certain initial potassium concentration ko_initial).
I looked at the potassium accumulation mechanism kext described in Example 6. I have two queries
First, would I be right in updating the values of ko and ki by using the same code as example 6, with the following changes:-
(a) I change the USEION statement so that it reads ik and writes ki,ko. I also add ki in the state block.
(b) I select the thickness of fh space so that I get the extracellular space volume that i desire (which is approx 20% of the volume of the soma in my case).
(c) I disregard the kbath by removing the second term from the following equation in the derivative block
ko' = (1e8)*ik/(fhspace*FARADAY) + (kbath - ko)/txfer
(c) I add another equation for intracellular K depletion as follows
ki' = (1e8)*(-ik)/(fhspace*FARADAY)
Second, how do i ensure that ik itself depends on the changed concentrations of ki and ko ?
thanks in advance
I am trying to create a mechanism that reads the potassium current ik and computes the values of ki and ko. What i also require is that ik should also be dependent on the newly modified values of ik and ko. The model that I have in mind is a single compartment soma(with a certain initial potassium concentration ki_initial) enveloped by a fixed volume of extracellular space (again with a certain initial potassium concentration ko_initial).
I looked at the potassium accumulation mechanism kext described in Example 6. I have two queries
First, would I be right in updating the values of ko and ki by using the same code as example 6, with the following changes:-
(a) I change the USEION statement so that it reads ik and writes ki,ko. I also add ki in the state block.
(b) I select the thickness of fh space so that I get the extracellular space volume that i desire (which is approx 20% of the volume of the soma in my case).
(c) I disregard the kbath by removing the second term from the following equation in the derivative block
ko' = (1e8)*ik/(fhspace*FARADAY) + (kbath - ko)/txfer
(c) I add another equation for intracellular K depletion as follows
ki' = (1e8)*(-ik)/(fhspace*FARADAY)
Second, how do i ensure that ik itself depends on the changed concentrations of ki and ko ?
thanks in advance