Hello Research Gate Community !
We are used to investigate rat aortic rings reactivity in organ bath to assess endothelial-dependent relaxation with acetylcholine, from phenylephrin (PE)-induced precontracted aortas.
However, we want now to switch on mice models to be able to use ko mice models as well and to have a more mechanistic approach.
However, we have some troubles to reproduce this technique in mice. Our basal tension is around 0.8g and the PE-induced contraction (10-6 M) leads to 1,30g maximal tension (mean around 1,20g) which we consider low. Do you think this alright, or we need to have a better contraction ? is this possible by the way ? We observe a good relaxation with an acetylcholine concentration at 10-5 M. Maybe do you use 2,5 mM for CaCl2 concentration in Krebs solution ? We tried at 1,25 mM as this more close to physiological condition.
Can you give us some advises maybe to have a better contraction ?
In advance, thank you very much.
Some ideas maybe :
- One or 2 precontraction with KCl (60 to 120 mM)
- Organ bath temperature well controlled
Hi Guillaume,
I encourage you to try a dose response to PE to obtain the Emax of PE on mouse aorta. From there, estimate the dose that produces ~80% of the maximum contraction to PE and use this as a preconstriction for your Ach dose response.
I preconstrict smaller mouse vessels (mesenteric and thoracodorsal arteries) with 10uM PE (10-5M) to 50uM and use 2mM CaCl2 in Krebs-Hepes. If you'd like more details, you can check out this paper: Article Characterization of the Thoracodorsal Artery: Morphology and...
Hope this helps!
-Marie