Acetylcholine is thought to play a role in

Explanation:

It's always interesting to look up something that you know nothing about. I have what is considered a very slow heart rate (47). I was called a liar by my Grade 8 teacher until she checked herself.

That's part of what this enzyme does. It slows the heart rate. Not that I claim to be in the same talent class as Wayne Gretzky but he also is noted for having a low heart rate. Both of us must have more than enough Acetylcholine.

It also controls blood vessel dilation (increase or decrease in the diameter). I also have high blood pressure if untreated which means I have to give up my claim to having more than enough Acetylcholine.

It also contracts muscles and controls the body's liquid secretions.  I have no comment about either of those.