The choline found in lecithin is used to make acetylcholine in the body.
Drug A attaches to the acetylcholine receptors on the smooth muscle without stimulating them and prevents acetylcholine from gaining access to them.
Also, choline is used to produce the important neurotransmitter acetylcholine.
They always use the neurotransmitter acetylcholine, and are always excitatory.
acetylcholine in the brain.