Which of the following has, among other effects, an excitatory effect on skeletal muscle fibres and an inhibitory effect on the muscles of the heart?
A) serotonin
B) endorphins
C) norepinephrine
D) acetylcholine

Question

Quizplus · Accepted Answer

Acetylcholine has an excitatory effect on skeletal muscle fibres, causing muscle contraction, and an inhibitory effect on the muscles of the heart, causing a decrease in heart rate. Serotonin, endorphins, and norepinephrine do not have this specific effect on skeletal and cardiac muscle.

Which of the Following Has, Among Other Effects, an Excitatory