I've read several studies analyzing vascular reactivity (mostly aorta, mesenteric and femoral arteries) using organ bath apparatus connected to a force transductor. Usually, the described protocols in "Material and Methods" session diverge from each other. One raised question is about how to determine the vessels endothelial integrity.
Some protocols state that relaxation induced by Ach should be superior to 10% maximal contraction triggered by phenylephrine. Some others declare that this limit should be 60%. Which protocol do you use as basis (reference)? Which concentrations of Ach and Phe do you use to veriry vessel's integrity and which parameter do you use?
Thanks in advance!
Go to Current protocols in Pharmacology and take out the protocol from there.
Ach Induced relaxation depends upon its bath concentration, Moreover what dose of PE are you using to contract the tissue is also important. Your question is not clear whether you just want to check the integrity of endothelium or you want to test your drugs on it. Ach is the best agent for endothelial integrity checking.
Hi Patrick,
I use 10% limit when I want to see if I successfully removed the endothelium or not. If it shows a response greater than 10% that means removal wasn't complete. I use 80% (some use 60%) value to see if the endothelium is at full health. If the relaxation response is 60-80% of PE that means endothelium integrity is intact. Just be careful while determining this and use Ach atleast 10 times higher than PE. Like I contract aorta with 10^-7 PE and check integrity with 10^-6 Ach. Hope that helps.
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