Acetylcholine is known to increase the contractility of smooth muscle. And norepinephrine is known to decrease the contractility of smooth muscle. Oxytocin is a hormone that causes uterine contractions. Correct?
I did an experiment with a lab rat. We removed the ovaries and then injected the rat with oil and another rat with estrogen. After a week we removed the uterine horns and placed it on a force transducer to record its contractions with acetylcholine added to the uterine horn, then norepinephrine was added and then oxytocin was added. All the results make sense except I'm having trouble with the duration results. In my results ach has decreased, epi has increased and oxytocin has increased. (Which I expected so I have no problem with oxytocin) But why ach and epi? I thought ach would increase the contractions and it would increase over time. I thought epi would decrease because it was known to decrease muscle contractions. I'm really confused.
Can any one help?