- ACh (Acetylcholine) : - ACh (Acetylcholine ) : ACh is the short form of Acetylcholine which refers to a type of neurotransmitter. It is a chemical that is used by neurons to communicate with other neurons and with parts of the body. It is also used by the part of the nervous system that is responsible for resting and digesting. It causes the lowers blood pressure and slows down heart rate and breathing rate. ACh is also known as Choline.