How to generate stress using Land17 active tension model in bench?

Question

Hi,

I would like to use the plug-in "Stress_Land17" in combination with the OHara or Tomek ionic model. Unfortunately, I'm not able to get it to work. There is (almost) no stress generated and the intracellular calcium is 0 throughout the whole simulation. It seems like the intracellular calcium from the ionic model is not correctly coupled to the plug-in since the Ca_i time series output by the ionic models seems normal.

I also tried to use a combination of Land12 and the Augustin model bc it said in the preamble of the Augustin model that it was implemented in order to be coupled to the Land12 model specificially, but I have a similar problem here that the intracellular calcium in the stress model is always at 0.

I'm using only default parameters and I run the command "bench --imp OHara --plug-in Stress_Land17". Is there something I need to do additionally to tell openCARP to use the intracellular calcium of the ionic model in the tension model? Or is there maybe a minimum working example with the Land model coupled to any ionic model?

Thank you

Jonathan

Answer 1

Fixed it partly. The problem was that in the Stress_Land17 model the external variable that was read in was called "Ca_i" while it is called "Cai" in OHara and therefore there was no calcium input to the Land model. Now at least for multiple stimuli it generates multiple tension peaks but they still don't look how they are supposed to

Answer 2

Hi Jonathan,

I will look at this and will get back to you as soon I have an answer. However, I recommend opening an issue in  openCARP issues.

Cheers,

Jorge

Comments

Hi Jonathan,

After looking at the ionic model you need to take care of the units of Cai. Cai in the ionic model should be in micromolar. In the ionic models Cai is usually in millimolar.

Cheers,

Jorge